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Karaboga S, Severac F, Collins EMS, Stab A, Davis A, Souchet M, Hervé G. Organophosphate toxicity patterns: A new approach for assessing organophosphate neurotoxicity. JOURNAL OF HAZARDOUS MATERIALS 2024; 470:134236. [PMID: 38613959 DOI: 10.1016/j.jhazmat.2024.134236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 03/30/2024] [Accepted: 04/06/2024] [Indexed: 04/15/2024]
Abstract
Organophosphorus compounds or organophosphates (OPs) are widely used as flame retardants, plasticizers, lubricants and pesticides. This contributes to their ubiquitous presence in the environment and to the risk of human exposure. The persistence of OPs and their bioaccumulative characteristics raise serious concerns regarding environmental and human health impacts. To address the need for safer OPs, this study uses a New Approach Method (NAM) to analyze the neurotoxicity pattern of 42 OPs. The NAM consists of a 4-step process that combines computational modeling with in vitro and in vivo experimental studies. Using spherical harmonic-based cluster analysis, the OPs were grouped into four main clusters. Experimental data and quantitative structure-activity relationships (QSARs) analysis were used in conjunction to provide information on the neurotoxicity profile of each group. Results showed that one of the identified clusters had a favorable safety profile, which may help identify safer OPs for industrial applications. In addition, the 3D-computational analysis of each cluster was used to identify meta-molecules with specific 3D features. Toxicity was found to correspond to the level of phosphate surface accessibility. Substances with conformations that minimize phosphate surface accessibility caused less neurotoxic effect. This multi-assay NAM could be used as a guide for the classification of OP toxicity, helping to minimize the health and environmental impacts of OPs, and providing rapid support to the chemical regulators, whilst reducing reliance on animal testing.
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Affiliation(s)
- Sinan Karaboga
- Harmonic Pharma, Campus Artem 92, rue du Sergent Blandan, 54000 Nancy, France
| | - Florence Severac
- R&D Laboratory and Technical Department, NYCO, 75008 Paris, France
| | | | - Aurélien Stab
- Harmonic Pharma, Campus Artem 92, rue du Sergent Blandan, 54000 Nancy, France
| | - Audrey Davis
- UniCaen, Université de Caen Normandie, Normandie, CERMN, 14000 Caen, France
| | - Michel Souchet
- Harmonic Pharma, Campus Artem 92, rue du Sergent Blandan, 54000 Nancy, France
| | - Grégoire Hervé
- R&D Laboratory and Technical Department, NYCO, 75008 Paris, France.
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2
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Hunt PR, Welch B, Camacho J, Bushana PN, Rand H, Sprando RL, Ferguson M. The worm Adult Activity Test (wAAT): A de novo mathematical model for detecting acute chemical effects in Caenorhabditis elegans. J Appl Toxicol 2023; 43:1899-1915. [PMID: 37551865 DOI: 10.1002/jat.4525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 07/05/2023] [Accepted: 07/20/2023] [Indexed: 08/09/2023]
Abstract
We have adapted a semiautomated method for tracking Caenorhabditis elegans spontaneous locomotor activity into a quantifiable assay by developing a sophisticated method for analyzing the time course of measured activity. The 16-h worm Adult Activity Test (wAAT) can be used to measure C. elegans activity levels for efficient screening for pharmacological and toxicity-induced effects. As with any apical endpoint assay, the wAAT is mode of action agnostic, allowing for detection of effects from a broad spectrum of response pathways. With caffeine as a model mild stimulant, the wAAT showed transient hyperactivity followed by reversion to baseline. Mercury chloride (HgCl2 ) produced an early dose-response hyperactivity phase followed by pronounced hypoactivity, a behavior pattern we have termed a toxicant "escape response." Methylmercury chloride (meHgCl) produced a similar pattern to HgCl2 , but at much lower concentrations, a weaker hyperactivity response, and more pronounced hypoactivity. Sodium arsenite (NaAsO2 ) and dimethylarsinic acid (DMA) induced hypoactivity at high concentrations. Acute toxicity, as measured by hypoactivity in C. elegans adults, was ranked: meHgCl > HgCl2 > NaAsO2 = DMA. Caffeine was not toxic with the wAAT at tested concentrations. Methods for conducting the wAAT are described, along with instructions for preparing C. elegans Habitation Medium, a liquid nutrient medium that allows for developmental timing equivalent to that found with C. elegans grown on agar with OP50 Escherichia coli feeder cultures. A de novo mathematical parametric model for adult C. elegans activity and the application of this model in ranking exposure toxicity are presented.
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Affiliation(s)
- Piper Reid Hunt
- Division of Toxicology, Office of Applied Research and Safety Assessment, Center for Food Safety and Applied Nutrition, United States Food and Drug Administration, Laurel, Maryland, USA
| | - Bonnie Welch
- Division of Toxicology, Office of Applied Research and Safety Assessment, Center for Food Safety and Applied Nutrition, United States Food and Drug Administration, Laurel, Maryland, USA
| | - Jessica Camacho
- Division of Toxicology, Office of Applied Research and Safety Assessment, Center for Food Safety and Applied Nutrition, United States Food and Drug Administration, Laurel, Maryland, USA
| | - Priyanka N Bushana
- Department of Translational Medicine and Physiology, Washington State University - Health Science Campus, Pullman, Washington, USA
| | - Hugh Rand
- Biostatistics and Bioinformatics Staff, Office of Analytics and Outreach, Center for Food Safety and Applied Nutrition, United States Food and Drug Administration, College Park, Maryland, USA
| | - Robert L Sprando
- Division of Toxicology, Office of Applied Research and Safety Assessment, Center for Food Safety and Applied Nutrition, United States Food and Drug Administration, Laurel, Maryland, USA
| | - Martine Ferguson
- Biostatistics and Bioinformatics Staff, Office of Analytics and Outreach, Center for Food Safety and Applied Nutrition, United States Food and Drug Administration, College Park, Maryland, USA
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von Hellfeld R, Gade C, Baumann L, Leist M, Braunbeck T. The sensitivity of the zebrafish embryo coiling assay for the detection of neurotoxicity by compounds with diverse modes of action. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023:10.1007/s11356-023-27662-2. [PMID: 37213015 DOI: 10.1007/s11356-023-27662-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 05/11/2023] [Indexed: 05/23/2023]
Abstract
In the aim to determine neurotoxicity, new methods are being validated, including tests and test batteries comprising in vitro and in vivo approaches. Alternative test models such as the zebrafish (Danio rerio) embryo have received increasing attention, with minor modifications of the fish embryo toxicity test (FET; OECD TG 236) as a tool to assess behavioral endpoints related to neurotoxicity during early developmental stages. The spontaneous tail movement assay, also known as coiling assay, assesses the development of random movement into complex behavioral patterns and has proven sensitive to acetylcholine esterase inhibitors at sublethal concentrations. The present study explored the sensitivity of the assay to neurotoxicants with other modes of action (MoAs). Here, five compounds with diverse MoAs were tested at sublethal concentrations: acrylamide, carbaryl, hexachlorophene, ibuprofen, and rotenone. While carbaryl, hexachlorophene, and rotenone consistently induced severe behavioral alterations by ~ 30 h post fertilization (hpf), acrylamide and ibuprofen expressed time- and/or concentration-dependent effects. At 37-38 hpf, additional observations revealed behavioral changes during dark phases with a strict concentration-dependency. The study documented the applicability of the coiling assay to MoA-dependent behavioral alterations at sublethal concentrations, underlining its potential as a component of a neurotoxicity test battery.
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Affiliation(s)
- Rebecca von Hellfeld
- School of Biological Sciences, University of Aberdeen, 23 St Machar Drive, Aberdeen, AB24 3UK, UK.
- National Decommissioning Centre, Main Street, Ellon, AB41 6AA, UK.
- Aquatic Ecology and Toxicology, Centre for Organismal Studies, University of Heidelberg, Im Neuenheimer Feld 504, 69120, Heidelberg, Germany.
| | - Christoph Gade
- School of Biological Sciences, University of Aberdeen, 23 St Machar Drive, Aberdeen, AB24 3UK, UK
- National Decommissioning Centre, Main Street, Ellon, AB41 6AA, UK
- Aquatic Ecology and Toxicology, Centre for Organismal Studies, University of Heidelberg, Im Neuenheimer Feld 504, 69120, Heidelberg, Germany
| | - Lisa Baumann
- Aquatic Ecology and Toxicology, Centre for Organismal Studies, University of Heidelberg, Im Neuenheimer Feld 504, 69120, Heidelberg, Germany
- Faculty of Science, Environmental Health & Toxicology, Vrije Universiteit Amsterdam, De Boelelaan 1105, 1081 HV, Amersterdam, Netherlands
| | - Marcel Leist
- In Vitro Toxicology and Biomedicine, Department Inaugurated By the Doerenkamp-Zbinden Foundation, University of Konstanz, Universitätsstraße 10, 78464, Constance, Germany
| | - Thomas Braunbeck
- Aquatic Ecology and Toxicology, Centre for Organismal Studies, University of Heidelberg, Im Neuenheimer Feld 504, 69120, Heidelberg, Germany
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Han X, Matsuda N, Ishibashi Y, Odawara A, Takahashi S, Tooi N, Kinoshita K, Suzuki I. A functional neuron maturation device provides convenient application on microelectrode array for neural network measurement. Biomater Res 2022; 26:84. [PMID: 36539898 PMCID: PMC9768978 DOI: 10.1186/s40824-022-00324-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 11/17/2022] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Microelectrode array (MEA) systems are valuable for in vitro assessment of neurotoxicity and drug efficiency. However, several difficulties such as protracted functional maturation and high experimental costs hinder the use of MEA analysis requiring human induced pluripotent stem cells (hiPSCs). Neural network functional parameters are also needed for in vitro to in vivo extrapolation. METHODS In the present study, we produced a cost effective nanofiber culture platform, the SCAD device, for long-term culture of hiPSC-derived neurons and primary peripheral neurons. The notable advantage of SCAD device is convenient application on multiple MEA systems for neuron functional analysis. RESULTS We showed that the SCAD device could promote functional maturation of cultured hiPSC-derived neurons, and neurons responded appropriately to convulsant agents. Furthermore, we successfully analyzed parameters for in vitro to in vivo extrapolation, i.e., low-frequency components and synaptic propagation velocity of the signal, potentially reflecting neural network functions from neurons cultured on SCAD device. Finally, we measured the axonal conduction velocity of peripheral neurons. CONCLUSIONS Neurons cultured on SCAD devices might constitute a reliable in vitro platform to investigate neuron functions, drug efficacy and toxicity, and neuropathological mechanisms by MEA.
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Affiliation(s)
- Xiaobo Han
- grid.444756.00000 0001 2165 0596Department of Electronics, Graduate School of Engineering, Tohoku Institute of Technology, 35-1 Yagiyama Kasumicho, Taihaku-Ku, Sendai, Miyagi 982-8577 Japan
| | - Naoki Matsuda
- grid.444756.00000 0001 2165 0596Department of Electronics, Graduate School of Engineering, Tohoku Institute of Technology, 35-1 Yagiyama Kasumicho, Taihaku-Ku, Sendai, Miyagi 982-8577 Japan
| | - Yuto Ishibashi
- grid.444756.00000 0001 2165 0596Department of Electronics, Graduate School of Engineering, Tohoku Institute of Technology, 35-1 Yagiyama Kasumicho, Taihaku-Ku, Sendai, Miyagi 982-8577 Japan
| | - Aoi Odawara
- grid.444756.00000 0001 2165 0596Department of Electronics, Graduate School of Engineering, Tohoku Institute of Technology, 35-1 Yagiyama Kasumicho, Taihaku-Ku, Sendai, Miyagi 982-8577 Japan
| | - Sayuri Takahashi
- grid.444756.00000 0001 2165 0596Department of Electronics, Graduate School of Engineering, Tohoku Institute of Technology, 35-1 Yagiyama Kasumicho, Taihaku-Ku, Sendai, Miyagi 982-8577 Japan
| | - Norie Tooi
- Stem Cell & Device Laboratory, Inc. (SCAD), OFFICE-ONE Shijo Karasuma 11F, 480, Niwatoriboko-Cho, Shimogyo-Ku, Kyoto, 600-8491 Japan
| | - Koshi Kinoshita
- Stem Cell & Device Laboratory, Inc. (SCAD), OFFICE-ONE Shijo Karasuma 11F, 480, Niwatoriboko-Cho, Shimogyo-Ku, Kyoto, 600-8491 Japan
| | - Ikuro Suzuki
- grid.444756.00000 0001 2165 0596Department of Electronics, Graduate School of Engineering, Tohoku Institute of Technology, 35-1 Yagiyama Kasumicho, Taihaku-Ku, Sendai, Miyagi 982-8577 Japan
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de Leeuw VC, van Oostrom CTM, Wackers PFK, Pennings JLA, Hodemaekers HM, Piersma AH, Hessel EVS. Neuronal differentiation pathways and compound-induced developmental neurotoxicity in the human neural progenitor cell test (hNPT) revealed by RNA-seq. CHEMOSPHERE 2022; 304:135298. [PMID: 35700809 PMCID: PMC9247748 DOI: 10.1016/j.chemosphere.2022.135298] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 05/30/2022] [Accepted: 06/08/2022] [Indexed: 05/27/2023]
Abstract
There is an increased awareness that the use of animals for compound-induced developmental neurotoxicity (DNT) testing has limitations. Animal-free innovations, especially the ones based on human stem cell-based models are pivotal in studying DNT since they can mimic processes relevant to human brain development. Here we present the human neural progenitor test (hNPT), a 10-day protocol in which neural progenitor cells differentiate into a neuron-astrocyte co-culture. The study aimed to characterise differentiation over time and to find neurodevelopmental processes sensitive to compound exposure using transcriptomics. 3992 genes regulated in unexposed control cultures (p ≤ 0.001, log2FC ≥ 1) showed Gene Ontology (GO-) term enrichment for neuronal and glial differentiation, neurite extension, synaptogenesis, and synaptic transmission. Exposure to known or suspected DNT compounds (acrylamide, chlorpyrifos, fluoxetine, methyl mercury, or valproic acid) at concentrations resulting in 95% cell viability each regulated unique combinations of GO-terms relating to neural progenitor proliferation, neuronal and glial differentiation, axon development, synaptogenesis, synaptic transmission, and apoptosis. Investigation of the GO-terms 'neuron apoptotic process' and 'axon development' revealed common genes that were responsive across compounds, and might be used as biomarkers for DNT. The GO-term 'synaptic signalling', on the contrary, whilst also responsive to all compounds tested, showed little overlap in gene expression regulation patterns between the conditions. This GO-term may articulate compound-specific effects that may be relevant for revealing differences in mechanism of toxicity. Given its focus on neural progenitor cell to mature multilineage neuronal cell maturation and its detailed molecular readout based on gene expression analysis, hNPT might have added value as a tool for neurodevelopmental toxicity testing in vitro. Further assessment of DNT-specific biomarkers that represent these processes needs further studies.
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Affiliation(s)
- Victoria C de Leeuw
- Centre for Health Protection, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands; Institute for Risk Assessment Sciences (IRAS), Utrecht University, Utrecht, the Netherlands.
| | - Conny T M van Oostrom
- Centre for Health Protection, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands
| | - Paul F K Wackers
- Centre for Health Protection, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands
| | - Jeroen L A Pennings
- Centre for Health Protection, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands
| | - Hennie M Hodemaekers
- Centre for Health Protection, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands
| | - Aldert H Piersma
- Centre for Health Protection, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands; Institute for Risk Assessment Sciences (IRAS), Utrecht University, Utrecht, the Netherlands
| | - Ellen V S Hessel
- Centre for Health Protection, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands
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6
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Zhang L, Li S, Xia M. High-Throughput Neurite Outgrowth Assay Using GFP-Labeled iPSC-Derived Neurons. Curr Protoc 2022; 2:e542. [PMID: 36102902 PMCID: PMC9635626 DOI: 10.1002/cpz1.542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The potential neurotoxicity from an increasing number of drugs and untested environmental chemicals creates a need to develop reliable and efficient in vitro methods for identifying chemicals that may adversely affect the nervous system. An important process in neurodevelopment is neurite outgrowth, which can be affected by developmental neurotoxicity. Currently, neurite outgrowth assays rely mainly on staining, which requires multiple sample processing steps, particularly washing steps, that may introduce variation and limit throughput. Here, we describe a neurite outgrowth assay that uses induced pluripotent stem cell (iPSC)-derived human cortical glutamatergic neurons and/or spinal motor neurons labeled with green fluorescent protein (GFP) to test compounds in a high-content and high-throughput format. This method enables live and time-lapse imaging of GFP-labeled neurons using an assay plate that is continuously imaged at multiple times after chemical treatment. In this article, we describe how to thaw frozen GFP-labeled neurons, culture them, treat them with a compound of interest, and analyze neurite outgrowth using a high-content imaging platform. In this assay, GFP-labeled iPSC-derived human neurons represent a promising tool for identifying and prioritizing compounds with potential developmental neurotoxicity for further hazard characterization. © 2022 The Authors. Current Protocols published by Wiley Periodicals LLC. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA. Basic Protocol 1: Thawing and seeding of iPSC-derived neurons Basic Protocol 2: Compound plate preparation and treatment of neurons Basic Protocol 3: High-content imaging and analysis.
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Affiliation(s)
- Li Zhang
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD, USA
| | - Shuaizhang Li
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD, USA
| | - Menghang Xia
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD, USA
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7
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Lee J, Schlichting R, König M, Scholz S, Krauss M, Escher BI. Monitoring Mixture Effects of Neurotoxicants in Surface Water and Wastewater Treatment Plant Effluents with Neurite Outgrowth Inhibition in SH-SY5Y Cells. ACS ENVIRONMENTAL AU 2022; 2:523-535. [PMID: 37101724 PMCID: PMC10125335 DOI: 10.1021/acsenvironau.2c00026] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 07/20/2022] [Accepted: 07/21/2022] [Indexed: 11/30/2022]
Abstract
Cell-based assays covering environmentally relevant modes of action are widely used for water quality monitoring. However, no high-throughput assays are available for testing developmental neurotoxicity of water samples. We implemented an assay that quantifies neurite outgrowth, which is one of the neurodevelopmental key events, and cell viability in human neuroblastoma SH-SY5Y cells using imaging techniques. We used this assay for testing of extracts of surface water collected in agricultural areas during rain events and effluents from wastewater treatment plants (WWTPs), where more than 200 chemicals had been quantified. Forty-one chemicals were tested individually that were suspected to contribute to the mixture effects among the detected chemicals in environmental samples. Sample sensitivity distributions indicated higher neurotoxicity for surface water samples than for effluents, and the endpoint of neurite outgrowth inhibition was six times more sensitive than cytotoxicity in the surface water samples and only three times more sensitive in the effluent samples. Eight environmental pollutants showed high specificity, and those ranged from pharmaceuticals (mebendazole and verapamil) to pesticides (methiocarb and clomazone), biocides (1,2-benzisothiazolin-3-one), and industrial chemicals (N-methyl-2-pyrrolidone, 7-diethylamino-4-methylcoumarin, and 2-(4-morpholinyl)benzothiazole). Although neurotoxic effects were newly detected for some of our test chemicals, less than 1% of the measured effects were explained by the detected and toxicologically characterized chemicals. The neurotoxicity assay was benchmarked against other bioassays: activations of the aryl hydrocarbon receptor and the peroxisome proliferator-activated receptor were similar in sensitivity, highly sensitive and did not differ much between the two water types, with surface water having slightly higher effects than the WWTP effluent. Oxidative stress response mirrored neurotoxicity quite well but was caused by different chemicals in the two water types. Overall, the new cell-based neurotoxicity assay is a valuable complement to the existing battery of effect-based monitoring tools.
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Affiliation(s)
- Jungeun Lee
- Department of Cell Toxicology, Helmholtz Centre for Environmental Research−UFZ, DE-04318 Leipzig, Germany
| | - Rita Schlichting
- Department of Cell Toxicology, Helmholtz Centre for Environmental Research−UFZ, DE-04318 Leipzig, Germany
| | - Maria König
- Department of Cell Toxicology, Helmholtz Centre for Environmental Research−UFZ, DE-04318 Leipzig, Germany
| | - Stefan Scholz
- Department of Bioanalytical Ecotoxicology, Helmholtz Centre for Environmental Research−UFZ, DE-04318 Leipzig, Germany
| | - Martin Krauss
- Department of Effect-Directed Analysis, Helmholtz Centre for Environmental Research−UFZ, DE-04318 Leipzig, Germany
| | - Beate I. Escher
- Department of Cell Toxicology, Helmholtz Centre for Environmental Research−UFZ, DE-04318 Leipzig, Germany
- Environmental Toxicology, Center for Applied Geoscience, Eberhard Karls University Tübingen, DE-72076 Tübingen, Germany
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8
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Crofton KM, Bassan A, Behl M, Chushak YG, Fritsche E, Gearhart JM, Marty MS, Mumtaz M, Pavan M, Ruiz P, Sachana M, Selvam R, Shafer TJ, Stavitskaya L, Szabo DT, Szabo ST, Tice RR, Wilson D, Woolley D, Myatt GJ. Current status and future directions for a neurotoxicity hazard assessment framework that integrates in silico approaches. COMPUTATIONAL TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2022; 22:100223. [PMID: 35844258 PMCID: PMC9281386 DOI: 10.1016/j.comtox.2022.100223] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
Abstract
Neurotoxicology is the study of adverse effects on the structure or function of the developing or mature adult nervous system following exposure to chemical, biological, or physical agents. The development of more informative alternative methods to assess developmental (DNT) and adult (NT) neurotoxicity induced by xenobiotics is critically needed. The use of such alternative methods including in silico approaches that predict DNT or NT from chemical structure (e.g., statistical-based and expert rule-based systems) is ideally based on a comprehensive understanding of the relevant biological mechanisms. This paper discusses known mechanisms alongside the current state of the art in DNT/NT testing. In silico approaches available today that support the assessment of neurotoxicity based on knowledge of chemical structure are reviewed, and a conceptual framework for the integration of in silico methods with experimental information is presented. Establishing this framework is essential for the development of protocols, namely standardized approaches, to ensure that assessments of NT and DNT based on chemical structures are generated in a transparent, consistent, and defendable manner.
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Affiliation(s)
| | - Arianna Bassan
- Innovatune srl, Via Giulio Zanon 130/D, 35129 Padova,
Italy
| | - Mamta Behl
- Division of the National Toxicology Program, National
Institutes of Environmental Health Sciences, Durham, NC 27709, USA
| | - Yaroslav G. Chushak
- Henry M Jackson Foundation for the Advancement of Military
Medicine, Wright-Patterson AFB, OH 45433, USA
| | - Ellen Fritsche
- IUF – Leibniz Research Institute for Environmental
Medicine & Medical Faculty Heinrich-Heine-University, Düsseldorf,
Germany
| | - Jeffery M. Gearhart
- Henry M Jackson Foundation for the Advancement of Military
Medicine, Wright-Patterson AFB, OH 45433, USA
| | | | - Moiz Mumtaz
- Agency for Toxic Substances and Disease Registry, US
Department of Health and Human Services, Atlanta, GA, USA
| | - Manuela Pavan
- Innovatune srl, Via Giulio Zanon 130/D, 35129 Padova,
Italy
| | - Patricia Ruiz
- Agency for Toxic Substances and Disease Registry, US
Department of Health and Human Services, Atlanta, GA, USA
| | - Magdalini Sachana
- Environment Health and Safety Division, Environment
Directorate, Organisation for Economic Co-Operation and Development (OECD), 75775
Paris Cedex 16, France
| | - Rajamani Selvam
- Office of Clinical Pharmacology, Office of Translational
Sciences, Center for Drug Evaluation and Research (CDER), U.S. Food and Drug
Administration (FDA), Silver Spring, MD 20993, USA
| | - Timothy J. Shafer
- Biomolecular and Computational Toxicology Division, Center
for Computational Toxicology and Exposure, US EPA, Research Triangle Park, NC,
USA
| | - Lidiya Stavitskaya
- Office of Clinical Pharmacology, Office of Translational
Sciences, Center for Drug Evaluation and Research (CDER), U.S. Food and Drug
Administration (FDA), Silver Spring, MD 20993, USA
| | | | | | | | - Dan Wilson
- The Dow Chemical Company, Midland, MI 48667, USA
| | | | - Glenn J. Myatt
- Instem, Columbus, OH 43215, USA
- Corresponding author.
(G.J. Myatt)
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9
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Inhibition of neurite outgrowth and enhanced effects compared to baseline toxicity in SH-SY5Y cells. Arch Toxicol 2022; 96:1039-1053. [PMID: 35182163 PMCID: PMC8921145 DOI: 10.1007/s00204-022-03237-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 01/27/2022] [Indexed: 01/19/2023]
Abstract
Early life exposure to environmental chemicals can cause developmental neurotoxicity (DNT). The impairment of key neurodevelopmental processes such as neurite outgrowth inhibition can be used as endpoints for screening of DNT effects. We quantified neurite-specific effects using the ratio of effect concentrations for cytotoxicity and neurite outgrowth inhibition (SRcytotoxicity). Baseline cytotoxicity, the minimal toxicity of any chemical, was used to quantify enhanced cytotoxicity (toxic ratio, TR) and neuronal-specific toxicity (SRbaseline) by comparing baseline cytotoxicity with the effects on cell viability and neurite outgrowth, respectively. The effects on cell viability and neurite length were measured based on image analysis in human neuroblastoma SH-SY5Y cells. Baseline cytotoxicity was predicted from hydrophobicity descriptors using a previously published model for SH-SY5Y cells. Enhanced cytotoxicity and neuronal-specific toxicity were more often observed for hydrophilic chemicals, which indicates that they are more likely to act through specific modes of action (MOA) on cell viability and neurite outgrowth. Hydrophobic chemicals showed a tendency to act through baseline toxicity without showing specific or enhanced toxicity, but were highly potent considering their low effect concentrations for both cytotoxicity and neurite outgrowth inhibition. The endpoint-specific controls (narciclasine, colchicine, cycloheximide, and rotenone), two carbamates (3-hydroxycarbofuran and carbaryl), and two redox cyclers (diquat and paraquat) showed distinct neurite-specific effects (SRcytotoxicity > 4). By comparing neurite-specific effects with enhanced cytotoxicity, one can explain whether the observed effects involve specific inhibition of neurite outgrowth, other specific MOAs, or merely baseline toxicity arising from hydrophobicity.
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10
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Culbreth M, Nyffeler J, Willis C, Harrill JA. Optimization of Human Neural Progenitor Cells for an Imaging-Based High-Throughput Phenotypic Profiling Assay for Developmental Neurotoxicity Screening. FRONTIERS IN TOXICOLOGY 2022; 3:803987. [PMID: 35295155 PMCID: PMC8915842 DOI: 10.3389/ftox.2021.803987] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 12/27/2021] [Indexed: 11/13/2022] Open
Abstract
Studies in in vivo rodent models have been the accepted approach by regulatory agencies to evaluate potential developmental neurotoxicity (DNT) of chemicals for decades. These studies, however, are inefficient and cannot meet the demand for the thousands of chemicals that need to be assessed for DNT hazard. As such, several in vitro new approach methods (NAMs) have been developed to circumvent limitations of these traditional studies. The DNT NAMs, some of which utilize human-derived cell models, are intended to be employed in a testing battery approach, each focused on a specific neurodevelopmental process. The need for multiple assays, however, to evaluate each process can prolong testing and prioritization of chemicals for more in depth assessments. Therefore, a multi-endpoint higher-throughput approach to assess DNT hazard potential would be of value. Accordingly, we have adapted a high-throughput phenotypic profiling (HTPP) approach for use with human-derived neural progenitor (hNP1) cells. HTPP is a fluorescence-based assay that quantitatively measures alterations in cellular morphology. This approach, however, required optimization of several laboratory procedures prior to chemical screening. First, we had to determine an appropriate cell plating density in 384-well plates. We then had to identify the minimum laminin concentration required for optimal cell growth and attachment. And finally, we had to evaluate whether addition of antibiotics to the culture medium would alter cellular morphology. We selected 6,000 cells/well as an appropriate plating density, 20 µg/ml laminin for optimal cell growth and attachment, and antibiotic addition in the culture medium. After optimizing hNP1 cell culture conditions for HTPP, it was then necessary to select appropriate in-plate assay controls from a reference chemical set. These reference chemicals were previously demonstrated to elicit unique phenotypic profiles in various other cell types. Aphidicolin, bafilomycin A1, berberine chloride, and cucurbitacin I induced robust phenotypic profiles as compared to dimethyl sulfoxide vehicle control in the hNP1 cells, and thus can be employed as in-plate assay controls for subsequent chemical screens. We have optimized HTPP for hNP1 cells, and consequently this approach can now be assessed as a potential NAM for DNT hazard evaluation and results compared to previously developed DNT assays.
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Affiliation(s)
- Megan Culbreth
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Durham, NC, United States
| | - Johanna Nyffeler
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Durham, NC, United States
- Oak Ridge Institute for Science and Education (ORISE) Postdoctoral Fellow, Oak Ridge, TN, United States
| | - Clinton Willis
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Durham, NC, United States
| | - Joshua A. Harrill
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Durham, NC, United States
- *Correspondence: Joshua A. Harrill,
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Looking at Developmental Neurotoxicity Testing from the Perspective of an Invertebrate Embryo. Int J Mol Sci 2022; 23:ijms23031871. [PMID: 35163796 PMCID: PMC8836978 DOI: 10.3390/ijms23031871] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 02/04/2022] [Accepted: 02/05/2022] [Indexed: 02/01/2023] Open
Abstract
Developmental neurotoxicity (DNT) of chemical compounds disrupts the formation of a normal brain. There is impressive progress in the development of alternative testing methods for DNT potential in chemicals, some of which also incorporate invertebrate animals. This review briefly touches upon studies on the genetically tractable model organisms of Caenorhabditis elegans and Drosophila melanogaster about the action of specific developmental neurotoxicants. The formation of a functional nervous system requires precisely timed axonal pathfinding to the correct cellular targets. To address this complex key event, our lab developed an alternative assay using a serum-free culture of intact locust embryos. The first neural pathways in the leg of embryonic locusts are established by a pair of afferent pioneer neurons which use guidance cues from membrane-bound and diffusible semaphorin proteins. In a systematic approach according to recommendations for alternative testing, the embryo assay quantifies defects in pioneer navigation after exposure to a panel of recognized test compounds for DNT. The outcome indicates a high predictability for test-compound classification. Since the pyramidal neurons of the mammalian cortex also use a semaphorin gradient for neurite guidance, the assay is based on evolutionary conserved cellular mechanisms, supporting its relevance for cortical development.
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12
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A framework for chemical safety assessment incorporating new approach methodologies within REACH. Arch Toxicol 2022; 96:743-766. [PMID: 35103819 PMCID: PMC8850243 DOI: 10.1007/s00204-021-03215-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 12/21/2021] [Indexed: 12/15/2022]
Abstract
The long-term investment in new approach methodologies (NAMs) within the EU and other parts of the world is beginning to result in an emerging consensus of how to use information from in silico, in vitro and targeted in vivo sources to assess the safety of chemicals. However, this methodology is being adopted very slowly for regulatory purposes. Here, we have developed a framework incorporating in silico, in vitro and in vivo methods designed to meet the requirements of REACH in which both hazard and exposure can be assessed using a tiered approach. The outputs from each tier are classification categories, safe doses, and risk assessments, and progress through the tiers depends on the output from previous tiers. We have exemplified the use of the framework with three examples. The outputs were the same or more conservative than parallel assessments based on conventional studies. The framework allows a transparent and phased introduction of NAMs in chemical safety assessment and enables science-based safety decisions which provide the same level of public health protection using fewer animals, taking less time, and using less financial and expert resource. Furthermore, it would also allow new methods to be incorporated as they develop through continuous selective evolution rather than periodic revolution.
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13
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Acute effects of the imidacloprid metabolite desnitro-imidacloprid on human nACh receptors relevant for neuronal signaling. Arch Toxicol 2021; 95:3695-3716. [PMID: 34628512 PMCID: PMC8536575 DOI: 10.1007/s00204-021-03168-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 09/20/2021] [Indexed: 12/15/2022]
Abstract
Several neonicotinoids have recently been shown to activate the nicotinic acetylcholine receptor (nAChR) on human neurons. Moreover, imidacloprid (IMI) and other members of this pesticide family form a set of diverse metabolites within crops. Among these, desnitro-imidacloprid (DN-IMI) is of special toxicological interest, as there is evidence (i) for human dietary exposure to this metabolite, (ii) and that DN-IMI is a strong trigger of mammalian nicotinic responses. We set out here to quantify responses of human nAChRs to DN-IMI and an alternative metabolite, IMI-olefin. To evaluate toxicological hazards, these data were then compared to those of IMI and nicotine. Ca2+-imaging experiments on human neurons showed that DN-IMI exhibits an agonistic effect on nAChRs at sub-micromolar concentrations (equipotent with nicotine) while IMI-olefin activated the receptors less potently (in a similar range as IMI). Direct experimental data on the interaction with defined receptor subtypes were obtained by heterologous expression of various human nAChR subtypes in Xenopus laevis oocytes and measurement of the transmembrane currents evoked by exposure to putative ligands. DN-IMI acted on the physiologically important human nAChR subtypes α7, α3β4, and α4β2 (high-sensitivity variant) with similar potency as nicotine. IMI and IMI-olefin were confirmed as nAChR agonists, although with 2–3 orders of magnitude lower potency. Molecular docking studies, using receptor models for the α7 and α4β2 nAChR subtypes supported an activity of DN-IMI similar to that of nicotine. In summary, these data suggest that DN-IMI functionally affects human neurons similar to the well-established neurotoxicant nicotine by triggering α7 and several non-α7 nAChRs.
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Dolde X, Karreman C, Wiechers M, Schildknecht S, Leist M. Profiling of Human Neural Crest Chemoattractant Activity as a Replacement of Fetal Bovine Serum for In Vitro Chemotaxis Assays. Int J Mol Sci 2021; 22:ijms221810079. [PMID: 34576243 PMCID: PMC8468192 DOI: 10.3390/ijms221810079] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 09/09/2021] [Accepted: 09/14/2021] [Indexed: 12/27/2022] Open
Abstract
Fetal bovine serum (FBS) is the only known stimulus for the migration of human neural crest cells (NCCs). Non-animal chemoattractants are desirable for the optimization of chemotaxis as-says to be incorporated in a test battery for reproductive and developmental toxicity. We con-firmed here in an optimized transwell assay that FBS triggers directed migration along a con-centration gradient. The responsible factor was found to be a protein in the 30–100 kDa size range. In a targeted approach, we tested a large panel of serum constituents known to be chem-otactic for NCCs in animal models (e.g., VEGF, PDGF, FGF, SDF-1/CXCL12, ephrins, endothelin, Wnt, BMPs). None of the corresponding human proteins showed any effect in our chemotaxis assays based on human NCCs. We then examined, whether human cells would produce any fac-tor able to trigger NCC migration in a broad screening approach. We found that HepG2 hepa-toma cells produced chemotaxis-triggering activity (CTA). Using chromatographic methods and by employing the NCC chemotaxis test as bioassay, the responsible protein was enriched by up to 5000-fold. We also explored human serum and platelets as a direct source, independent of any cell culture manipulations. A CTA was enriched from platelet lysates several thousand-fold. Its temperature and protease sensitivity suggested also a protein component. The capacity of this factor to trigger chemotaxis was confirmed by single-cell video-tracking analysis of migrating NCCs. The human CTA characterized here may be employed in the future for the setup of assays testing for the disturbance of directed NCC migration by toxicants.
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Affiliation(s)
- Xenia Dolde
- Department of Biology, University of Konstanz, 78457 Konstanz, Germany; (X.D.); (C.K.); (M.W.)
| | - Christiaan Karreman
- Department of Biology, University of Konstanz, 78457 Konstanz, Germany; (X.D.); (C.K.); (M.W.)
| | - Marianne Wiechers
- Department of Biology, University of Konstanz, 78457 Konstanz, Germany; (X.D.); (C.K.); (M.W.)
| | - Stefan Schildknecht
- Department of Life Sciences, Albstadt-Sigmaringen University of Applied Sciences, 72488 Sigmaringen, Germany;
| | - Marcel Leist
- Department of Biology, University of Konstanz, 78457 Konstanz, Germany; (X.D.); (C.K.); (M.W.)
- Correspondence: ; Tel.: +49-(0)7531-88-5037; Fax: +49-(0)7531-88-5039
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15
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Chesnut M, Paschoud H, Repond C, Smirnova L, Hartung T, Zurich MG, Hogberg HT, Pamies D. Human IPSC-Derived Model to Study Myelin Disruption. Int J Mol Sci 2021; 22:ijms22179473. [PMID: 34502381 PMCID: PMC8430601 DOI: 10.3390/ijms22179473] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 08/27/2021] [Accepted: 08/28/2021] [Indexed: 12/15/2022] Open
Abstract
Myelin is of vital importance to the central nervous system and its disruption is related to a large number of both neurodevelopmental and neurodegenerative diseases. The differences observed between human and rodent oligodendrocytes make animals inadequate for modeling these diseases. Although developing human in vitro models for oligodendrocytes and myelinated axons has been a great challenge, 3D cell cultures derived from iPSC are now available and able to partially reproduce the myelination process. We have previously developed a human iPSC-derived 3D brain organoid model (also called BrainSpheres) that contains a high percentage of myelinated axons and is highly reproducible. Here, we have further refined this technology by applying multiple readouts to study myelination disruption. Myelin was assessed by quantifying immunostaining/confocal microscopy of co-localized myelin basic protein (MBP) with neurofilament proteins as well as proteolipid protein 1 (PLP1). Levels of PLP1 were also assessed by Western blot. We identified compounds capable of inducing developmental neurotoxicity by disrupting myelin in a systematic review to evaluate the relevance of our BrainSphere model for the study of the myelination/demyelination processes. Results demonstrated that the positive reference compound (cuprizone) and two of the three potential myelin disruptors tested (Bisphenol A, Tris(1,3-dichloro-2-propyl) phosphate, but not methyl mercury) decreased myelination, while ibuprofen (negative control) had no effect. Here, we define a methodology that allows quantification of myelin disruption and provides reference compounds for chemical-induced myelin disruption.
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Affiliation(s)
- Megan Chesnut
- Center for Alternatives to Animal Testing (CAAT), Johns Hopkins Bloomberg School of Public Health, 615 N Wolfe St., Baltimore, MD 21205, USA; (M.C.); (L.S.); (T.H.)
| | - Hélène Paschoud
- Department of Biomedical Sciences, University of Lausanne, CH-1005 Lausanne, Switzerland; (H.P.); (C.R.); (M.-G.Z.)
| | - Cendrine Repond
- Department of Biomedical Sciences, University of Lausanne, CH-1005 Lausanne, Switzerland; (H.P.); (C.R.); (M.-G.Z.)
| | - Lena Smirnova
- Center for Alternatives to Animal Testing (CAAT), Johns Hopkins Bloomberg School of Public Health, 615 N Wolfe St., Baltimore, MD 21205, USA; (M.C.); (L.S.); (T.H.)
| | - Thomas Hartung
- Center for Alternatives to Animal Testing (CAAT), Johns Hopkins Bloomberg School of Public Health, 615 N Wolfe St., Baltimore, MD 21205, USA; (M.C.); (L.S.); (T.H.)
- Center for Alternative to Animla Testing Europe, University of Konstanz, 78464 Konstanz, Germany
| | - Marie-Gabrielle Zurich
- Department of Biomedical Sciences, University of Lausanne, CH-1005 Lausanne, Switzerland; (H.P.); (C.R.); (M.-G.Z.)
- Swiss Centre for Applied Human Toxicology (SCAHT), 4055 Basel, Switzerland
| | - Helena T. Hogberg
- Center for Alternatives to Animal Testing (CAAT), Johns Hopkins Bloomberg School of Public Health, 615 N Wolfe St., Baltimore, MD 21205, USA; (M.C.); (L.S.); (T.H.)
- Correspondence: (H.T.H.); (D.P.)
| | - David Pamies
- Center for Alternatives to Animal Testing (CAAT), Johns Hopkins Bloomberg School of Public Health, 615 N Wolfe St., Baltimore, MD 21205, USA; (M.C.); (L.S.); (T.H.)
- Department of Biomedical Sciences, University of Lausanne, CH-1005 Lausanne, Switzerland; (H.P.); (C.R.); (M.-G.Z.)
- Swiss Centre for Applied Human Toxicology (SCAHT), 4055 Basel, Switzerland
- Correspondence: (H.T.H.); (D.P.)
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16
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Chesnut M, Hartung T, Hogberg H, Pamies D. Human Oligodendrocytes and Myelin In Vitro to Evaluate Developmental Neurotoxicity. Int J Mol Sci 2021; 22:7929. [PMID: 34360696 PMCID: PMC8347131 DOI: 10.3390/ijms22157929] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 07/14/2021] [Accepted: 07/21/2021] [Indexed: 01/01/2023] Open
Abstract
Neurodevelopment is uniquely sensitive to toxic insults and there are concerns that environmental chemicals are contributing to widespread subclinical developmental neurotoxicity (DNT). Increased DNT evaluation is needed due to the lack of such information for most chemicals in common use, but in vivo studies recommended in regulatory guidelines are not practical for the large-scale screening of potential DNT chemicals. It is widely acknowledged that developmental neurotoxicity is a consequence of disruptions to basic processes in neurodevelopment and that testing strategies using human cell-based in vitro systems that mimic these processes could aid in prioritizing chemicals with DNT potential. Myelination is a fundamental process in neurodevelopment that should be included in a DNT testing strategy, but there are very few in vitro models of myelination. Thus, there is a need to establish an in vitro myelination assay for DNT. Here, we summarize the routes of myelin toxicity and the known models to study this particular endpoint.
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Affiliation(s)
- Megan Chesnut
- Center for Alternatives to Animal Testing (CAAT), Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA; (M.C.); (T.H.)
| | - Thomas Hartung
- Center for Alternatives to Animal Testing (CAAT), Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA; (M.C.); (T.H.)
- Center for Alternatives to Animal Testing (CAAT-Europe), University of Konstanz, 78464 Konstanz, Germany
| | - Helena Hogberg
- Center for Alternatives to Animal Testing (CAAT), Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA; (M.C.); (T.H.)
| | - David Pamies
- Center for Alternatives to Animal Testing (CAAT), Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA; (M.C.); (T.H.)
- Department of Physiology, University of Lausanne, 1005 Lausanne, Switzerland
- Swiss Centre for Applied Human Toxicology (SCAHT), 4055 Basel, Switzerland
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17
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Atzei A, Jense I, Zwart EP, Legradi J, Venhuis BJ, van der Ven LT, Heusinkveld HJ, Hessel EV. Developmental Neurotoxicity of Environmentally Relevant Pharmaceuticals and Mixtures Thereof in a Zebrafish Embryo Behavioural Test. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18136717. [PMID: 34206423 PMCID: PMC8297305 DOI: 10.3390/ijerph18136717] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 06/09/2021] [Accepted: 06/17/2021] [Indexed: 11/16/2022]
Abstract
Humans are exposed daily to complex mixtures of chemical substances via food intake, inhalation, and dermal contact. Developmental neurotoxicity is an understudied area and entails one of the most complex areas in toxicology. Animal studies for developmental neurotoxicity (DNT) are hardly performed in the context of regular hazard studies, as they are costly and time consuming and provide only limited information as to human relevance. There is a need for a combination of in vitro and in silico tests for the assessment of chemically induced DNT in humans. The zebrafish (Danio rerio) embryo (ZFE) provides a powerful model to study DNT because it shows fast neurodevelopment with a large resemblance to the higher vertebrate, including the human system. One of the suitable readouts for DNT testing in the zebrafish is neurobehaviour (stimulus-provoked locomotion) since this provides integrated information on the functionality and status of the entire nervous system of the embryo. In the current study, environmentally relevant pharmaceuticals and their mixtures were investigated using the zebrafish light-dark transition test. Zebrafish embryos were exposed to three neuroactive compounds of concern, carbamazepine (CBZ), fluoxetine (FLX), and venlafaxine (VNX), as well as their main metabolites, carbamazepine 10,11-epoxide (CBZ 10,11E), norfluoxetine (norFLX), and desvenlafaxine (desVNX). All the studied compounds, except CBZ 10,11E, dose-dependently inhibited zebrafish locomotor activity, providing a distinct behavioural phenotype. Mixture experiments with these pharmaceuticals identified that dose addition was confirmed for all the studied binary mixtures (CBZ-FLX, CBZ-VNX, and VNX-FLX), thereby supporting the zebrafish embryo as a model for studying the cumulative effect of chemical mixtures in DNT. This study shows that pharmaceuticals and a mixture thereof affect locomotor activity in zebrafish. The test is directly applicable in environmental risk assessment; however, further studies are required to assess the relevance of these findings for developmental neurotoxicity in humans.
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Affiliation(s)
- Alessandro Atzei
- National Institute for Public Health and the Environment (RIVM), 3721 AB Bilthoven, The Netherlands; (A.A.); (I.J.); (E.P.Z.); (B.J.V.); (L.T.M.v.d.V.); (E.V.S.H.)
| | - Ingrid Jense
- National Institute for Public Health and the Environment (RIVM), 3721 AB Bilthoven, The Netherlands; (A.A.); (I.J.); (E.P.Z.); (B.J.V.); (L.T.M.v.d.V.); (E.V.S.H.)
| | - Edwin P. Zwart
- National Institute for Public Health and the Environment (RIVM), 3721 AB Bilthoven, The Netherlands; (A.A.); (I.J.); (E.P.Z.); (B.J.V.); (L.T.M.v.d.V.); (E.V.S.H.)
| | - Jessica Legradi
- Environment & Health, VU University Amsterdam, 1081 HV Amsterdam, The Netherlands;
| | - Bastiaan J. Venhuis
- National Institute for Public Health and the Environment (RIVM), 3721 AB Bilthoven, The Netherlands; (A.A.); (I.J.); (E.P.Z.); (B.J.V.); (L.T.M.v.d.V.); (E.V.S.H.)
| | - Leo T.M. van der Ven
- National Institute for Public Health and the Environment (RIVM), 3721 AB Bilthoven, The Netherlands; (A.A.); (I.J.); (E.P.Z.); (B.J.V.); (L.T.M.v.d.V.); (E.V.S.H.)
| | - Harm J. Heusinkveld
- National Institute for Public Health and the Environment (RIVM), 3721 AB Bilthoven, The Netherlands; (A.A.); (I.J.); (E.P.Z.); (B.J.V.); (L.T.M.v.d.V.); (E.V.S.H.)
- Correspondence:
| | - Ellen V.S. Hessel
- National Institute for Public Health and the Environment (RIVM), 3721 AB Bilthoven, The Netherlands; (A.A.); (I.J.); (E.P.Z.); (B.J.V.); (L.T.M.v.d.V.); (E.V.S.H.)
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18
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Kang SY, Joshi P, Lee MY. High-Throughput Screening of Compound Neurotoxicity Using 3D-Cultured Neural Stem Cells on a 384-Pillar Plate. Curr Protoc 2021; 1:e107. [PMID: 33887124 DOI: 10.1002/cpz1.107] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Assessing the neurotoxicity of test chemicals has typically been performed using two-dimensionally (2D)-cultured neuronal cell monolayers and animal models. The in vitro 2D cell models are simple and straightforward compared to animal models, which have the disadvantage of being relatively low throughput, expensive, and time consuming. Despite their extensive use in this area of neurotoxicology research, both models often do not accurately recapitulate human outcomes. To bridge this gap and attempt to better replicate what happens in vivo, three-dimensionally (3D) cultured neural stem cells (NSCs) encapsulated in hydrogels on a 384-pillar plate have been developed via miniature 3D bioprinting. This technology allows users to print NSCs on a pillar plate for rapid 3D cell culture as well as high-throughput compound screening. For this, the 384-pillar plate with bioprinted NSCs is sandwiched with a standard 384-well plate with growth medium for 3D culture, allowing researchers to expose the cells to test compounds and stain them with various fluorescent dyes for a suite of high-content imaging assays, including assays for DNA damage, mitochondrial impairment, cell membrane integrity, intracellular glutathione levels, and apoptosis. After acquiring cell images from an automated fluorescence microscope and extracting fluorescence intensities, researchers can obtain the IC50 value of each compound to evaluate critical parameters in neurotoxicity. Here, we provide a detailed description of protocols for cell printing on a 384-pillar plate, 3D NSC culture, compound testing, 3D cell staining, and image acquisition and analysis, which altogether will allow researchers to investigate mechanisms of compound neurotoxicity with 3D-cultured NSCs in a high-throughput manner. © 2021 Wiley Periodicals LLC. Basic Protocol 1: Three-dimensional neural stem cell culture on a 384-pillar plate Basic Protocol 2: Compound treatment and cell staining Basic Protocol 3: Image acquisition, processing, and data analysis.
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Affiliation(s)
- Soo-Yeon Kang
- Department of Chemical and Biomedical Engineering, Cleveland State University, Cleveland, Ohio
| | - Pranav Joshi
- Department of Chemical and Biomedical Engineering, Cleveland State University, Cleveland, Ohio
| | - Moo-Yeal Lee
- Department of Chemical and Biomedical Engineering, Cleveland State University, Cleveland, Ohio
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19
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Hernández‐Jerez A, Adriaanse P, Aldrich A, Berny P, Coja T, Duquesne S, Focks A, Marinovich M, Millet M, Pelkonen O, Pieper S, Tiktak A, Topping C, Widenfalk A, Wilks M, Wolterink G, Crofton K, Hougaard Bennekou S, Paparella M, Tzoulaki I. Development of Integrated Approaches to Testing and Assessment (IATA) case studies on developmental neurotoxicity (DNT) risk assessment. EFSA J 2021. [DOI: 10.2903/j.efsa.2021.6599] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
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20
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Schmitz A, Dempewolf S, Tan S, Bicker G, Stern M. Developmental Neurotoxicity of Fipronil and Rotenone on a Human Neuronal In Vitro Test System. Neurotox Res 2021; 39:1189-1202. [PMID: 33871813 PMCID: PMC8275550 DOI: 10.1007/s12640-021-00364-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 04/07/2021] [Accepted: 04/13/2021] [Indexed: 11/26/2022]
Abstract
Pesticide exposure during in utero and early postnatal development can cause a wide range of neurological defects. However, relatively few insecticides have been recognized as developmental neurotoxicants, so far. Recently, discovery of the insecticide, fipronil, in chicken eggs has raised public concern. The status of fipronil as a potential developmental neurotoxicant is still under debate. Whereas several in vivo and in vitro studies suggest specific toxicity, other in vitro studies could not confirm this concern. Here, we tested fipronil and its main metabolic product, fipronil sulfone both at concentrations between 1.98 and 62.5 µM, alongside with the established developmental neurotoxicant, rotenone (0.004-10 µM) in vitro on the human neuronal precursor cell line NT2. We found that rotenone impaired all three tested DNT endpoints, neurite outgrowth, neuronal differentiation, and precursor cell migration in a dose-dependent manner and clearly separable from general cytotoxicity in the nanomolar range. Fipronil and fipronil sulfone specifically inhibited cell migration and neuronal differentiation, but not neurite outgrowth in the micromolar range. The rho-kinase inhibitor Y-27632 counteracted inhibition of migration for all three compounds (EC50 between 12 and 50 µM). The antioxidant, n-acetyl cysteine, could ameliorate the inhibitory effects of fipronil on all three tested endpoints (EC 50 between 84 and 164 µM), indicating the involvement of oxidative stress. Fipronil sulfone had a stronger effect than fipronil, confirming the importance to test metabolic products alongside original pesticides. We conclude that in vitro fipronil and fipronil sulfone display specific developmental neurotoxicity on developing human model neurons.
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Affiliation(s)
- Anne Schmitz
- Institute of Physiology and Cell Biology, University of Veterinary Medicine Hannover, Bischofsholer Damm 15/102, 30173, Hannover, Germany
| | - Silke Dempewolf
- Institute of Physiology and Cell Biology, University of Veterinary Medicine Hannover, Bischofsholer Damm 15/102, 30173, Hannover, Germany
| | - Saime Tan
- Institute of Physiology and Cell Biology, University of Veterinary Medicine Hannover, Bischofsholer Damm 15/102, 30173, Hannover, Germany
| | - Gerd Bicker
- Institute of Physiology and Cell Biology, University of Veterinary Medicine Hannover, Bischofsholer Damm 15/102, 30173, Hannover, Germany
| | - Michael Stern
- Institute of Physiology and Cell Biology, University of Veterinary Medicine Hannover, Bischofsholer Damm 15/102, 30173, Hannover, Germany.
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Loser D, Hinojosa MG, Blum J, Schaefer J, Brüll M, Johansson Y, Suciu I, Grillberger K, Danker T, Möller C, Gardner I, Ecker GF, Bennekou SH, Forsby A, Kraushaar U, Leist M. Functional alterations by a subgroup of neonicotinoid pesticides in human dopaminergic neurons. Arch Toxicol 2021; 95:2081-2107. [PMID: 33778899 PMCID: PMC8166715 DOI: 10.1007/s00204-021-03031-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 03/17/2021] [Indexed: 12/16/2022]
Abstract
Neonicotinoid pesticides, originally developed to target the insect nervous system, have been reported to interact with human receptors and to activate rodent neurons. Therefore, we evaluated in how far these compounds may trigger signaling in human neurons, and thus, affect the human adult or developing nervous system. We used SH-SY5Y neuroblastoma cells as established model of nicotinic acetylcholine receptor (nAChR) signaling. In parallel, we profiled dopaminergic neurons, generated from LUHMES neuronal precursor cells, as novel system to study nAChR activation in human post-mitotic neurons. Changes of the free intracellular Ca2+ concentration ([Ca2+]i) were used as readout, and key findings were confirmed by patch clamp recordings. Nicotine triggered typical neuronal signaling responses that were blocked by antagonists, such as tubocurarine and mecamylamine. Pharmacological approaches suggested a functional expression of α7 and non-α7 nAChRs on LUHMES cells. In this novel test system, the neonicotinoids acetamiprid, imidacloprid, clothianidin and thiacloprid, but not thiamethoxam and dinotefuran, triggered [Ca2+]i signaling at 10-100 µM. Strong synergy of the active neonicotinoids (at low micromolar concentrations) with the α7 nAChR-positive allosteric modulator PNU-120596 was observed in LUHMES and SH-SY5Y cells, and specific antagonists fully inhibited such signaling. To provide a third line of evidence for neonicotinoid signaling via nAChR, we studied cross-desensitization: pretreatment of LUHMES and SH-SY5Y cells with active neonicotinoids (at 1-10 µM) blunted the signaling response of nicotine. The pesticides (at 3-30 µM) also blunted the response to the non-α7 agonist ABT 594 in LUHMES cells. These data show that human neuronal cells are functionally affected by low micromolar concentrations of several neonicotinoids. An effect of such signals on nervous system development is a toxicological concern.
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Affiliation(s)
- Dominik Loser
- NMI Natural and Medical Sciences Institute at the University of Tübingen, 72770, Reutlingen, Germany
- NMI TT GmbH, 72770, Reutlingen, Germany
- In Vitro Toxicology and Biomedicine, Department Inaugurated by the Doerenkamp-Zbinden Foundation, University of Konstanz, Universitaetsstr. 10, 78457, Konstanz, Germany
| | - Maria G Hinojosa
- Department of Biochemistry and Biophysics, Stockholm University, 106 91, Stockholm, Sweden
| | - Jonathan Blum
- In Vitro Toxicology and Biomedicine, Department Inaugurated by the Doerenkamp-Zbinden Foundation, University of Konstanz, Universitaetsstr. 10, 78457, Konstanz, Germany
| | - Jasmin Schaefer
- NMI Natural and Medical Sciences Institute at the University of Tübingen, 72770, Reutlingen, Germany
- NMI TT GmbH, 72770, Reutlingen, Germany
| | - Markus Brüll
- In Vitro Toxicology and Biomedicine, Department Inaugurated by the Doerenkamp-Zbinden Foundation, University of Konstanz, Universitaetsstr. 10, 78457, Konstanz, Germany
| | - Ylva Johansson
- Department of Biochemistry and Biophysics, Stockholm University, 106 91, Stockholm, Sweden
| | - Ilinca Suciu
- In Vitro Toxicology and Biomedicine, Department Inaugurated by the Doerenkamp-Zbinden Foundation, University of Konstanz, Universitaetsstr. 10, 78457, Konstanz, Germany
| | - Karin Grillberger
- Department of Pharmaceutical Sciences, University of Vienna, Vienna, Austria
| | - Timm Danker
- NMI Natural and Medical Sciences Institute at the University of Tübingen, 72770, Reutlingen, Germany
- NMI TT GmbH, 72770, Reutlingen, Germany
| | - Clemens Möller
- Life Sciences Faculty, Albstadt-Sigmaringen University, 72488, Sigmaringen, Germany
| | - Iain Gardner
- CERTARA UK Limited, Simcyp Division, Level 2-Acero, 1 Concourse Way, Sheffield, S1 2BJ, UK
| | - Gerhard F Ecker
- Department of Pharmaceutical Sciences, University of Vienna, Vienna, Austria
| | | | - Anna Forsby
- Department of Biochemistry and Biophysics, Stockholm University, 106 91, Stockholm, Sweden
| | - Udo Kraushaar
- NMI Natural and Medical Sciences Institute at the University of Tübingen, 72770, Reutlingen, Germany
| | - Marcel Leist
- In Vitro Toxicology and Biomedicine, Department Inaugurated by the Doerenkamp-Zbinden Foundation, University of Konstanz, Universitaetsstr. 10, 78457, Konstanz, Germany.
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22
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Toward a Better Testing Paradigm for Developmental Neurotoxicity: OECD Efforts and Regulatory Considerations. BIOLOGY 2021; 10:biology10020086. [PMID: 33498772 PMCID: PMC7912397 DOI: 10.3390/biology10020086] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 01/09/2021] [Accepted: 01/18/2021] [Indexed: 12/11/2022]
Abstract
Simple Summary It is recognized that the current developmental neurotoxicity (DNT) testing paradigm is not fit-for -purpose for the assessment of a large number of chemicals. In the last two decades there have been scientific advances made for evaluating chemical interactions with the developing nervous system that rely on alternative to animal methods. The Organisation for Economic Co-Operation and Development (OECD) provides a forum to develop internationally harmonised guidance to test and assess chemicals for DNT that is primarily based on cellular models. Given the complexity of the developing nervous system and the availability of a number of non-animal methods to address DNT, integration of data from multiple studies is necessary and an OECD framework for organising existing scientific knowledge can be applied as the canvas of this integration. Herein, we provide a brief overview of the OECD DNT project and summarize various achievements of relevance to the project. The review also presents an opportunity to describe considerations for uptake of the DNT non animal methods in a regulatory context. Abstract Characterization of potential chemical-induced developmental neurotoxicity (DNT) hazard is considered for risk assessment purposes by many regulatory sectors. However, due to test complexity, difficulty in interpreting results and need of substantial resources, the use of the in vivo DNT test guidelines has been limited and animal data on DNT are scarce. To address challenging endpoints such as DNT, the Organisation for Economic Co-Operation and Development (OECD) chemical safety program has been working lately toward the development of integrated approaches for testing and assessment (IATA) that rely on a combination of multiple layers of data (e.g., in vitro, in silico and non-mammalian in vivo models) that are supported by mechanistic knowledge organized according to the adverse outcome pathway (AOP) framework. In 2017, the OECD convened a dedicated OECD expert group to develop a guidance document on the application and interpretation of data derived from a DNT testing battery that relies on key neurodevelopmental processes and is complemented by zebrafish assays. This review will provide a brief overview of the OECD DNT project and summarize various achievements of relevance to the project. The review also presents an opportunity to describe considerations for uptake of the DNT in an in vitro battery in a regulatory context.
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23
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Hogberg HT, de Cássia da Silveira E Sá R, Kleensang A, Bouhifd M, Cemiloglu Ulker O, Smirnova L, Behl M, Maertens A, Zhao L, Hartung T. Organophosphorus flame retardants are developmental neurotoxicants in a rat primary brainsphere in vitro model. Arch Toxicol 2021; 95:207-228. [PMID: 33078273 PMCID: PMC7811506 DOI: 10.1007/s00204-020-02903-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 09/02/2020] [Indexed: 12/26/2022]
Abstract
Due to regulatory bans and voluntary substitutions, halogenated polybrominated diphenyl ether (PBDE) flame retardants (FR) are increasingly substituted by mainly organophosphorus FR (OPFR). Leveraging a 3D rat primary neural organotypic in vitro model (rat brainsphere), we compare developmental neurotoxic effects of BDE-47-the most abundant PBDE congener-with four OPFR (isopropylated phenyl phosphate-IPP, triphenyl phosphate-TPHP, isodecyl diphenyl phosphate-IDDP, and tricresyl phosphate (also known as trimethyl phenyl phosphate)-TMPP). Employing mass spectroscopy-based metabolomics and transcriptomics, we observe at similar human-relevant non-cytotoxic concentrations (0.1-5 µM) stronger developmental neurotoxic effects by OPFR. This includes toxicity to neurons in the low µM range; all FR decrease the neurotransmitters glutamate and GABA (except BDE-47 and TPHP). Furthermore, n-acetyl aspartate (NAA), considered a neurologic diagnostic molecule, was decreased by all OPFR. At similar concentrations, the FR currently in use decreased plasma membrane dopamine active transporter expression, while BDE-47 did not. Several findings suggest astrogliosis induced by the OPFR, but not BDE-47. At the 5 µM concentrations, the OPFR more than BDE-47 interfered with myelination. An increase of cytokine gene and receptor expressions suggests that exposure to OPFR may induce an inflammatory response. Pathway/category overrepresentation shows disruption in 1) transmission of action potentials, cell-cell signaling, synaptic transmission, receptor signaling, (2) immune response, inflammation, defense response, (3) cell cycle and (4) lipids metabolism and transportation. Taken together, this appears to be a case of regretful substitution with substances not less developmentally neurotoxic in a primary rat 3D model.
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Affiliation(s)
- Helena T Hogberg
- Center for Alternatives To Animal Testing (CAAT), Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
| | - Rita de Cássia da Silveira E Sá
- Center for Alternatives To Animal Testing (CAAT), Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
- Department of Physiology and Pathology, Federal University of Paraíba, João Pessoa, Brazil
| | - Andre Kleensang
- Center for Alternatives To Animal Testing (CAAT), Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Mounir Bouhifd
- Center for Alternatives To Animal Testing (CAAT), Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Ozge Cemiloglu Ulker
- Center for Alternatives To Animal Testing (CAAT), Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
- Department of Toxicology, Faculty of Pharmacy, Ankara University, Ankara, Turkey
| | - Lena Smirnova
- Center for Alternatives To Animal Testing (CAAT), Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Mamta Behl
- National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, Durham, NC, USA
| | - Alexandra Maertens
- Center for Alternatives To Animal Testing (CAAT), Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Liang Zhao
- Center for Alternatives To Animal Testing (CAAT), Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
- Bloomberg~Kimmel Institute for Cancer Immunotherapy, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Thomas Hartung
- Center for Alternatives To Animal Testing (CAAT), Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
- CAAT-Europe, University of Konstanz, Konstanz, Germany
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24
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Rosca A, Coronel R, Moreno M, González R, Oniga A, Martín A, López V, González MDC, Liste I. Impact of environmental neurotoxic: current methods and usefulness of human stem cells. Heliyon 2020; 6:e05773. [PMID: 33376823 PMCID: PMC7758368 DOI: 10.1016/j.heliyon.2020.e05773] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 11/10/2020] [Accepted: 12/15/2020] [Indexed: 12/12/2022] Open
Abstract
The development of central nervous system is a highly coordinated and complex process. Any alteration of this process can lead to disturbances in the structure and function of the brain, which can cause deficits in neurological development, resulting in neurodevelopmental disorders, including, for example, autism or attention-deficit hyperactivity disorder. Exposure to certain chemicals during the fetal period and childhood is known to cause developmental neurotoxicity and has serious consequences that persist into adult life. For regulatory purposes, determination of the potential for developmental neurotoxicity is performed according the OECD Guideline 426, in which the test substance is administered to animals during gestation and lactation. However, these animal models are expensive, long-time consuming and may not reflect the physiology in humans; that makes it an unsustainable model to test the large amount of existing chemical products, hence alternative models to the use of animals are needed. One of the most promising methods is based on the use of stem cell technology. Stem cells are undifferentiated cells with the ability to self-renew and differentiate into more specialized cell types. Because of these properties, these cells have gained increased attention as possible therapeutic agents or as disease models. Here, we provide an overview of the current models both animal and cellular, available to study developmental neurotoxicity and review in more detail the usefulness of human stem cells, their properties and how they are becoming an alternative to evaluate and study the mechanisms of action of different environmental toxicants.
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Affiliation(s)
- Andreea Rosca
- Unidad de Regeneración Neural, Unidad Funcional de Investigación de Enfermedades Crónicas (UFIEC), Instituto de Salud Carlos III, Madrid, Spain
- Toxicología Ambiental, Centro Nacional de Sanidad Ambiental, Instituto de Salud Carlos III, Madrid, Spain
| | - Raquel Coronel
- Unidad de Regeneración Neural, Unidad Funcional de Investigación de Enfermedades Crónicas (UFIEC), Instituto de Salud Carlos III, Madrid, Spain
| | - Miryam Moreno
- Unidad de Regeneración Neural, Unidad Funcional de Investigación de Enfermedades Crónicas (UFIEC), Instituto de Salud Carlos III, Madrid, Spain
| | - Rosa González
- Unidad de Biología Computacional, Unidad Funcional de Investigación de Enfermedades Crónicas (UFIEC), Instituto de Salud Carlos III, Madrid, Spain
| | - Andreea Oniga
- Toxicología Ambiental, Centro Nacional de Sanidad Ambiental, Instituto de Salud Carlos III, Madrid, Spain
| | - Alberto Martín
- Instituto de Investigación de Enfermedades Raras (IIER), Instituto de Salud Carlos III, Madrid, Spain
| | - Victoria López
- Unidad de Biología Computacional, Unidad Funcional de Investigación de Enfermedades Crónicas (UFIEC), Instituto de Salud Carlos III, Madrid, Spain
| | - María del Carmen González
- Toxicología Ambiental, Centro Nacional de Sanidad Ambiental, Instituto de Salud Carlos III, Madrid, Spain
| | - Isabel Liste
- Unidad de Regeneración Neural, Unidad Funcional de Investigación de Enfermedades Crónicas (UFIEC), Instituto de Salud Carlos III, Madrid, Spain
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25
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A locust embryo as predictive developmental neurotoxicity testing system for pioneer axon pathway formation. Arch Toxicol 2020; 94:4099-4113. [PMID: 33079231 DOI: 10.1007/s00204-020-02929-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 10/08/2020] [Indexed: 12/31/2022]
Abstract
Exposure to environmental chemicals during in utero and early postnatal development can cause a wide range of neurological defects. Since current guidelines for identifying developmental neurotoxic chemicals depend on the use of large numbers of rodents in animal experiments, it has been proposed to design rapid and cost-efficient in vitro screening test batteries that are mainly based on mixed neuronal/glial cultures. However, cell culture tests do not assay correct wiring of neuronal circuits. The establishment of precise anatomical connectivity is a key event in the development of a functional brain. Here, we expose intact embryos of the locust (Locusta migratoria) in serum-free culture to test chemicals and visualize correct navigation of identified pioneer axons by fluorescence microscopy. We define separate toxicological endpoints for axonal elongation and navigation along a stereotyped pathway. To distinguish developmental neurotoxicity (DNT) from general toxicity, we quantify defects in axonal elongation and navigation in concentration-response curves and compare it to the biochemically determined viability of the embryo. The investigation of a panel of recognized DNT-positive and -negative test compounds supports a rather high predictability of this invertebrate embryo assay. Similar to the semaphorin-mediated guidance of neurites in mammalian cortex, correct axonal navigation of the locust pioneer axons relies on steering cues from members of this family of cell recognition molecules. Due to the evolutionary conserved mechanisms of neurite guidance, we suggest that our pioneer axon paradigm might provide mechanistically relevant information on the DNT potential of chemical agents on the processes of axon elongation, navigation, and fasciculation.
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26
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Barenys M, Illa M, Hofrichter M, Loreiro C, Pla L, Klose J, Kühne BA, Gómez-Catalán J, Braun JM, Crispi F, Gratacós E, Fritsche E. Rabbit neurospheres as a novel in vitro tool for studying neurodevelopmental effects induced by intrauterine growth restriction. Stem Cells Transl Med 2020; 10:209-221. [PMID: 33034168 PMCID: PMC7848321 DOI: 10.1002/sctm.20-0223] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 08/07/2020] [Accepted: 08/16/2020] [Indexed: 12/11/2022] Open
Abstract
The aim of this study was to develop a rabbit neurosphere culture to characterize differences in basic processes of neurogenesis induced by intrauterine growth restriction (IUGR). A novel in vitro neurosphere culture has been established using fresh or frozen neural progenitor cells from newborn (PND0) rabbit brains. After surgical IUGR induction in pregnant rabbits and cesarean section 5 days later, neural progenitor cells from both control and IUGR groups were isolated and directly cultured or frozen at −80°C. These neural progenitor cells spontaneously formed neurospheres after 7 days in culture. The ability of control and IUGR neurospheres to migrate, proliferate, differentiate to neurons, astrocytes, or oligodendrocytes was compared and the possibility to modulate their responses was tested by exposure to several positive and negative controls. Neurospheres obtained from IUGR brains have a significant impairment in oligodendrocyte differentiation, whereas no significant differences are observed in other basic processes of neurogenesis. This impairment can be reverted by in vitro exposure of IUGR neurospheres to thyroid hormone, which is known to play an essential role in white matter maturation in vivo. Our new rabbit neurosphere model and the results of this study open the possibility to test several substances in vitro as neuroprotective candidates against IUGR induced neurodevelopmental damage while decreasing the number of animals and resources and allowing a more mechanistic approach at a cellular functional level.
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Affiliation(s)
- Marta Barenys
- IUF-Leibniz Research Institute for Environmental Medicine, Düsseldorf, Germany.,GRET, INSA-UB and Toxicology Unit, Pharmacology, Toxicology and Therapeutical Chemistry Department, Faculty of Pharmacy, University of Barcelona, Barcelona, Spain
| | - Miriam Illa
- BCNatal-Barcelona Center for Maternal-Fetal and Neonatal Medicine (Hospital Clínic and Hospital Sant Joan de Déu), Fetal i+D Fetal Medicine Research Center, IDIBAPS, University of Barcelona, Center for Biomedical Research on Rare Diseases (CIBER-ER), Barcelona, Spain
| | - Maxi Hofrichter
- IUF-Leibniz Research Institute for Environmental Medicine, Düsseldorf, Germany
| | - Carla Loreiro
- BCNatal-Barcelona Center for Maternal-Fetal and Neonatal Medicine (Hospital Clínic and Hospital Sant Joan de Déu), Fetal i+D Fetal Medicine Research Center, IDIBAPS, University of Barcelona, Center for Biomedical Research on Rare Diseases (CIBER-ER), Barcelona, Spain
| | - Laura Pla
- BCNatal-Barcelona Center for Maternal-Fetal and Neonatal Medicine (Hospital Clínic and Hospital Sant Joan de Déu), Fetal i+D Fetal Medicine Research Center, IDIBAPS, University of Barcelona, Center for Biomedical Research on Rare Diseases (CIBER-ER), Barcelona, Spain
| | - Jördis Klose
- IUF-Leibniz Research Institute for Environmental Medicine, Düsseldorf, Germany
| | - Britta Anna Kühne
- GRET, INSA-UB and Toxicology Unit, Pharmacology, Toxicology and Therapeutical Chemistry Department, Faculty of Pharmacy, University of Barcelona, Barcelona, Spain.,BCNatal-Barcelona Center for Maternal-Fetal and Neonatal Medicine (Hospital Clínic and Hospital Sant Joan de Déu), Fetal i+D Fetal Medicine Research Center, IDIBAPS, University of Barcelona, Center for Biomedical Research on Rare Diseases (CIBER-ER), Barcelona, Spain
| | - Jesús Gómez-Catalán
- GRET, INSA-UB and Toxicology Unit, Pharmacology, Toxicology and Therapeutical Chemistry Department, Faculty of Pharmacy, University of Barcelona, Barcelona, Spain
| | - Jan Matthias Braun
- IUF-Leibniz Research Institute for Environmental Medicine, Düsseldorf, Germany
| | - Fatima Crispi
- BCNatal-Barcelona Center for Maternal-Fetal and Neonatal Medicine (Hospital Clínic and Hospital Sant Joan de Déu), Fetal i+D Fetal Medicine Research Center, IDIBAPS, University of Barcelona, Center for Biomedical Research on Rare Diseases (CIBER-ER), Barcelona, Spain
| | - Eduard Gratacós
- BCNatal-Barcelona Center for Maternal-Fetal and Neonatal Medicine (Hospital Clínic and Hospital Sant Joan de Déu), Fetal i+D Fetal Medicine Research Center, IDIBAPS, University of Barcelona, Center for Biomedical Research on Rare Diseases (CIBER-ER), Barcelona, Spain
| | - Ellen Fritsche
- IUF-Leibniz Research Institute for Environmental Medicine, Düsseldorf, Germany
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27
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Attoff K, Johansson Y, Cediel-Ulloa A, Lundqvist J, Gupta R, Caiment F, Gliga A, Forsby A. Acrylamide alters CREB and retinoic acid signalling pathways during differentiation of the human neuroblastoma SH-SY5Y cell line. Sci Rep 2020; 10:16714. [PMID: 33028897 PMCID: PMC7541504 DOI: 10.1038/s41598-020-73698-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 09/21/2020] [Indexed: 01/06/2023] Open
Abstract
Acrylamide (ACR) is a known neurotoxicant which crosses the blood–brain barrier, passes the placenta and has been detected in breast milk. Hence, early-life exposure to ACR could lead to developmental neurotoxicity. The aim of this study was to elucidate if non-cytotoxic concentrations of ACR alter neuronal differentiation by studying gene expression of markers significant for neurodevelopment in the human neuroblastoma SH-SY5Y cell model. Firstly, by using RNASeq we identified two relevant pathways that are activated during 9 days of retinoic acid (RA) induced differentiation i.e. RA receptor (RAR) activation and the cAMP response element-binding protein (CREB) signalling pathways. Next, by qPCR we showed that 1 and 70 µM ACR after 9 days exposure alter the expression of 13 out of 36 genes in the RAR activation pathway and 18 out of 47 in the CREB signalling pathway. Furthermore, the expression of established neuronal markers i.e. BDNF, STXBP2, STX3, TGFB1 and CHAT were down-regulated. Decreased protein expression of BDNF and altered ratio of phosphorylated CREB to total CREB were confirmed by western blot. Our results reveal that micromolar concentrations of ACR sustain proliferation, decrease neurite outgrowth and interfere with signalling pathways involved in neuronal differentiation in the SH-SY5Y cell model.
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Affiliation(s)
- Kristina Attoff
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Ylva Johansson
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Andrea Cediel-Ulloa
- Unit of Toxicology Sciences, Swedish Toxicology Sciences Research Center (Swetox), Karolinska Institutet, Södertälje, Sweden.,Department for organismal biology, Uppsala University, Uppsala, Sweden
| | - Jessica Lundqvist
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden.,Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Rajinder Gupta
- Department of Toxicogenomics, School of Oncology and Developmental Biology (GROW), Maastricht University, Maastricht, The Netherlands
| | - Florian Caiment
- Department of Toxicogenomics, School of Oncology and Developmental Biology (GROW), Maastricht University, Maastricht, The Netherlands
| | - Anda Gliga
- Unit of Toxicology Sciences, Swedish Toxicology Sciences Research Center (Swetox), Karolinska Institutet, Södertälje, Sweden
| | - Anna Forsby
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden. .,Department for organismal biology, Uppsala University, Uppsala, Sweden.
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28
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The EU-ToxRisk method documentation, data processing and chemical testing pipeline for the regulatory use of new approach methods. Arch Toxicol 2020; 94:2435-2461. [PMID: 32632539 PMCID: PMC7367925 DOI: 10.1007/s00204-020-02802-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 06/03/2020] [Indexed: 12/17/2022]
Abstract
Hazard assessment, based on new approach methods (NAM), requires the use of batteries of assays, where individual tests may be contributed by different laboratories. A unified strategy for such collaborative testing is presented. It details all procedures required to allow test information to be usable for integrated hazard assessment, strategic project decisions and/or for regulatory purposes. The EU-ToxRisk project developed a strategy to provide regulatorily valid data, and exemplified this using a panel of > 20 assays (with > 50 individual endpoints), each exposed to 19 well-known test compounds (e.g. rotenone, colchicine, mercury, paracetamol, rifampicine, paraquat, taxol). Examples of strategy implementation are provided for all aspects required to ensure data validity: (i) documentation of test methods in a publicly accessible database; (ii) deposition of standard operating procedures (SOP) at the European Union DB-ALM repository; (iii) test readiness scoring accoding to defined criteria; (iv) disclosure of the pipeline for data processing; (v) link of uncertainty measures and metadata to the data; (vi) definition of test chemicals, their handling and their behavior in test media; (vii) specification of the test purpose and overall evaluation plans. Moreover, data generation was exemplified by providing results from 25 reporter assays. A complete evaluation of the entire test battery will be described elsewhere. A major learning from the retrospective analysis of this large testing project was the need for thorough definitions of the above strategy aspects, ideally in form of a study pre-registration, to allow adequate interpretation of the data and to ensure overall scientific/toxicological validity.
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29
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Lupu D, Andersson P, Bornehag CG, Demeneix B, Fritsche E, Gennings C, Lichtensteiger W, Leist M, Leonards PEG, Ponsonby AL, Scholze M, Testa G, Tresguerres JAF, Westerink RHS, Zalc B, Rüegg J. The ENDpoiNTs Project: Novel Testing Strategies for Endocrine Disruptors Linked to Developmental Neurotoxicity. Int J Mol Sci 2020; 21:ijms21113978. [PMID: 32492937 PMCID: PMC7312023 DOI: 10.3390/ijms21113978] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 05/21/2020] [Accepted: 05/28/2020] [Indexed: 12/21/2022] Open
Abstract
Ubiquitous exposure to endocrine-disrupting chemicals (EDCs) has caused serious concerns about the ability of these chemicals to affect neurodevelopment, among others. Since endocrine disruption (ED)-induced developmental neurotoxicity (DNT) is hardly covered by the chemical testing tools that are currently in regulatory use, the Horizon 2020 research and innovation action ENDpoiNTs has been launched to fill the scientific and methodological gaps related to the assessment of this type of chemical toxicity. The ENDpoiNTs project will generate new knowledge about ED-induced DNT and aims to develop and improve in vitro, in vivo, and in silico models pertaining to ED-linked DNT outcomes for chemical testing. This will be achieved by establishing correlative and causal links between known and novel neurodevelopmental endpoints and endocrine pathways through integration of molecular, cellular, and organismal data from in vitro and in vivo models. Based on this knowledge, the project aims to provide adverse outcome pathways (AOPs) for ED-induced DNT and to develop and integrate new testing tools with high relevance for human health into European and international regulatory frameworks.
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Affiliation(s)
- Diana Lupu
- Evolutionary Biology Centre, Uppsala University, 75236 Uppsala, Sweden;
- Institute of Environmental Medicine, Karolinska Institute, 17177 Stockholm, Sweden
- Department of Toxicology, Faculty of Pharmacy, Iuliu Hatieganu University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania
- Correspondence:
| | - Patrik Andersson
- Faculty of Science and Technology, Umeå University, 90187 Umeå, Sweden;
| | | | - Barbara Demeneix
- Evolution of Endocrine Regulations UMR 7221, Centre National de la Recherche Scientifique, 75005 Paris, France;
| | - Ellen Fritsche
- IUF—Leibniz Research Institute for Environmental Medicine, 40225 Düsseldorf, Germany;
| | - Chris Gennings
- Department of Environmental Medicine and Public Health, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA;
| | | | - Marcel Leist
- In Vitro Toxicology and Biomedicine, University of Konstanz, D-78457 Konstanz, Germany;
| | - Pim E. G. Leonards
- Department Environment and Health, Vrije University, 1081HV Amsterdam, The Netherlands;
| | - Anne-Louise Ponsonby
- Murdoch Children’s Research Institute, Royal Children’s Hospital, Parkville, Victoria 3052, Australia;
| | - Martin Scholze
- Institute of Environment, Health and Societies, Brunel University London, Uxbridge UB8 3PH, UK;
| | - Giuseppe Testa
- Department of Oncology and Hemato-Oncology, University of Milan, 20122 Milan, Italy;
| | - Jesus A. F. Tresguerres
- Department of Physiology, School of Medicine, Complutense University of Madrid, 28040 Madrid, Spain;
| | - Remco H. S. Westerink
- Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, 3584 CM Utrecht, The Netherlands;
| | - Bernard Zalc
- Sorbonne Université, Inserm, CNRS, ICM-GH Pitié-Salpêtrière, 75651 Paris, France;
| | - Joëlle Rüegg
- Evolutionary Biology Centre, Uppsala University, 75236 Uppsala, Sweden;
- Institute of Environmental Medicine, Karolinska Institute, 17177 Stockholm, Sweden
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30
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Abstract
The remarkable advances coming about through nanotechnology promise to revolutionize many aspects of modern life; however, these advances come with a responsibility for due diligence to ensure that they are not accompanied by adverse consequences for human health or the environment. Many novel nanomaterials (having at least one dimension <100 nm) could be highly mobile if released into the environment and are also very reactive, which has raised concerns for potential adverse impacts including, among others, the potential for neurotoxicity. Several lines of evidence led to concerns for neurotoxicity, but perhaps none more than observations that inhaled nanoparticles impinging on the mucosal surface of the nasal epithelium could be internalized into olfactory receptor neurons and transported by axoplasmic transport into the olfactory bulbs without crossing the blood-brain barrier. From the olfactory bulb, there is concern that nanomaterials may be transported deeper into the brain and affect other brain structures. Of course, people will not be exposed to only engineered nanomaterials, but rather such exposures will occur in a complex mixture of environmental materials, some of which are incidentally generated particles of a similar inhalable size range to engineered nanomaterials. To date, most experimental studies of potential neurotoxicity of nanomaterials have not considered the potential exposure sources and pathways that could lead to exposure, and most studies of nanomaterial exposure have not considered potential neurotoxicity. Here, we present a review of potential sources of exposures to nanoparticles, along with a review of the literature on potential neurotoxicity of nanomaterials. We employ the linked concepts of an aggregate exposure pathway (AEP) and an adverse outcome pathway (AOP) to organize and present the material. The AEP includes a sequence of key events progressing from material sources, release to environmental media, external exposure, internal exposure, and distribution to the target site. The AOP begins with toxicant at the target site causing a molecular initiating event and, like the AEP, progress sequentially to actions at the level of the cell, organ, individual, and population. Reports of nanomaterial actions are described at every key event along the AEP and AOP, except for changes in exposed populations that have not yet been observed. At this last stage, however, there is ample evidence of population level effects from exposure to ambient air particles that may act similarly to engineered nanomaterials. The data give an overall impression that current exposure levels may be considerably lower than those reported experimentally to be neurotoxic. This impression, however, is tempered by the absence of long-term exposure studies with realistic routes and levels of exposure to address concerns for chronic accumulation of materials or damage. Further, missing across the board are "key event relationships", which are quantitative expressions linking the key events of either the AEP or the AOP, making it impossible to quantitatively project the likelihood of adverse neurotoxic effects from exposure to nanomaterials or to estimate margins of exposure for such relationships.
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Affiliation(s)
- William K. Boyes
- Neurological and Endocrine Toxicology Branch, Public Health and Integrated Toxicology Division, Center for Public Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC USA 27711
| | - Christoph van Thriel
- Leibniz Research Centre for Working Environment and Human Factors, TU Dortmund, Ardeystr. 67, 44139 Dortmund, Germany
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31
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Carlson LM, Champagne FA, Cory-Slechta DA, Dishaw L, Faustman E, Mundy W, Segal D, Sobin C, Starkey C, Taylor M, Makris SL, Kraft A. Potential frameworks to support evaluation of mechanistic data for developmental neurotoxicity outcomes: A symposium report. Neurotoxicol Teratol 2020; 78:106865. [PMID: 32068112 PMCID: PMC7160758 DOI: 10.1016/j.ntt.2020.106865] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 02/05/2020] [Accepted: 02/10/2020] [Indexed: 12/16/2022]
Abstract
A key challenge in systematically incorporating mechanistic data into human health assessments is that, compared to studies of apical health endpoints, these data are both more abundant (mechanistic studies routinely outnumber other studies by several orders of magnitude) and more heterogeneous (e.g. different species, test system, tissue, cell type, exposure paradigm, or specific assays performed). A structured decision-making process for organizing, integrating, and weighing mechanistic DNT data for use in human health risk assessments will improve the consistency and efficiency of such evaluations. At the Developmental Neurotoxicology Society (DNTS) 2016 annual meeting, a symposium was held to address the application of existing organizing principles and frameworks for evaluation of mechanistic data relevant to interpreting neurotoxicology data. Speakers identified considerations with potential to advance the use of mechanistic DNT data in risk assessment, including considering the context of each exposure, since epigenetics, tissue type, sex, stress, nutrition and other factors can modify toxicity responses in organisms. It was also suggested that, because behavior is a manifestation of complex nervous system function, the presence and absence of behavioral change itself could be used to organize the interpretation of multiple complex simultaneous mechanistic changes. Several challenges were identified with frameworks and their implementation, and ongoing research to develop these approaches represents an early step toward full evaluation of mechanistic DNT data for assessments.
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Affiliation(s)
- Laura M Carlson
- Center for Public Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, RTP, NC.
| | | | - Deborah A Cory-Slechta
- Department of Environmental Medicine, University of Rochester Medical School Rochester, NY
| | - Laura Dishaw
- Center for Public Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, RTP, NC
| | - Elaine Faustman
- School of Public Health, Institute for Risk Analysis and Risk Communication, University of Washington, Seattle, WA
| | - William Mundy
- Neurotoxicologist, Durham, NC (formerly National Health and Environmental Effects Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, RTP, NC))
| | - Deborah Segal
- Center for Public Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Washington, DC
| | - Christina Sobin
- Dept of Public Health Sciences, The University of Texas at El Paso, El Paso, Texas, USA
| | - Carol Starkey
- Booz Allen Hamilton (formerly research fellow with the Oak Ridge Institute for Science and Engineering (ORISE) with Center for Public Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Washington DC))
| | - Michele Taylor
- Center for Public Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, RTP, NC
| | - Susan L Makris
- Center for Public Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Washington, DC
| | - Andrew Kraft
- Center for Public Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Washington, DC; Center for Public Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, RTP, NC
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32
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Bode K, Nolte L, Kamin H, Desens M, Ulmann A, Bergmann GA, Betker P, Reitmeier J, Ripken T, Stern M, Meyer H, Bicker G. Scanning laser optical tomography resolves developmental neurotoxic effects on pioneer neurons. Sci Rep 2020; 10:2641. [PMID: 32060340 PMCID: PMC7021824 DOI: 10.1038/s41598-020-59562-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 01/31/2020] [Indexed: 01/13/2023] Open
Abstract
Developmental neurotoxic compounds impair the developing human nervous system at lower doses than those affecting adults. Standardized test methods for assessing developmental neurotoxicity (DNT) require the use of high numbers of laboratory animals. Here, we use a novel assay that is based on the development of an intact insect embryo in serum-free culture. Neural pathways in the leg of embryonic locusts are established by a pair of afferent pioneer neurons, extending axons along a well-defined pathway to the central nervous system. After exposure to test chemicals, we analyze pioneer neuron shape with conventional fluorescence microscopy and compare it to 3D images, obtained by scanning laser optical tomography (SLOT) and processed by a segmentation algorithm. The segmented SLOT images resolve the 3D structure of the pioneers, recognize pathfinding defects and are thus advantageous for detecting DNT-positive compounds. The defects in axon elongation and pathfinding of pioneer axons caused by two DNT-positive reference compounds (methylmercury chloride; sodium(meta)arsenite) are compared to the biochemically measured general viability of the embryo. Using conventional fluorescence microscopy to establish concentration-response curves of axon elongation, we show that this assay identifies methylmercury chloride and the pro-apoptotic compound staurosporine as developmental neurotoxicants.
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Affiliation(s)
- Karsten Bode
- University of Veterinary Medicine Hannover, Institute of Physiology and Cell Biology, Bischofsholer Damm 15/102, 30173, Hannover, Germany
| | - Lena Nolte
- Laser Zentrum Hannover e.V., Industrial and Biomedical Optics Department, D-30419, Hannover, Germany
| | - Hannes Kamin
- Laser Zentrum Hannover e.V., Industrial and Biomedical Optics Department, D-30419, Hannover, Germany
| | - Michael Desens
- Laser Zentrum Hannover e.V., Industrial and Biomedical Optics Department, D-30419, Hannover, Germany
| | - Arthur Ulmann
- University of Veterinary Medicine Hannover, Institute of Physiology and Cell Biology, Bischofsholer Damm 15/102, 30173, Hannover, Germany
| | - Gregor A Bergmann
- University of Veterinary Medicine Hannover, Institute of Physiology and Cell Biology, Bischofsholer Damm 15/102, 30173, Hannover, Germany
| | - Philine Betker
- University of Veterinary Medicine Hannover, Institute of Physiology and Cell Biology, Bischofsholer Damm 15/102, 30173, Hannover, Germany
| | - Jennifer Reitmeier
- University of Veterinary Medicine Hannover, Institute of Physiology and Cell Biology, Bischofsholer Damm 15/102, 30173, Hannover, Germany
| | - Tammo Ripken
- Laser Zentrum Hannover e.V., Industrial and Biomedical Optics Department, D-30419, Hannover, Germany
| | - Michael Stern
- University of Veterinary Medicine Hannover, Institute of Physiology and Cell Biology, Bischofsholer Damm 15/102, 30173, Hannover, Germany
| | - Heiko Meyer
- Laser Zentrum Hannover e.V., Industrial and Biomedical Optics Department, D-30419, Hannover, Germany
| | - Gerd Bicker
- University of Veterinary Medicine Hannover, Institute of Physiology and Cell Biology, Bischofsholer Damm 15/102, 30173, Hannover, Germany.
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33
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Dach K, Yaghoobi B, Schmuck MR, Carty DR, Morales KM, Lein PJ. Teratological and Behavioral Screening of the National Toxicology Program 91-Compound Library in Zebrafish (Danio rerio). Toxicol Sci 2019; 167:77-91. [PMID: 30364989 DOI: 10.1093/toxsci/kfy266] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
To screen the tens of thousands of chemicals for which no toxicity data currently exists, it is necessary to move from in vivo rodent models to alternative models, such as zebrafish. Here, we used dechorionated Tropical 5D wild-type zebrafish embryos to screen a 91-compound library provided by the National Toxicology Program (NTP) for developmental toxicity. This library contained 86 unique chemicals that included negative controls, flame retardants, polycyclic aromatic hydrocarbons (PAHs), drugs, industrial chemicals, and pesticides. Fish were exposed to 5 concentrations of each chemical or an equal amount of vehicle (0.5% DMSO) in embryo medium from 6 h post-fertilization (hpf) to 5 days post-fertilization (dpf). Fish were examined daily for mortality and teratogenic effects and photomotor behavior was assessed at 4 and 5 dpf. Of the 5 negative control compounds in the library, none caused mortality/teratogenesis, but two altered behavior. Chemicals provided in duplicate produced similar outcomes. Overall, 13 compounds caused mortality/teratology but not behavioral abnormalities, 24 only affected behavior, and 18 altered both endpoints, with behavior affected at concentrations that did not cause mortality/teratology (55/86 hits). Of the compounds that affected behavior, 52% caused behavioral abnormalities at either 4 or 5 dpf. Compounds within the same functional group caused different behavioral abnormalities, while similar behavioral patterns were caused by compounds from different groups. Our data suggest that behavior is a sensitive endpoint for developmental toxicity screening that integrates multiple modes of toxic action and is influenced by the age of the larval fish at the time of testing.
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Affiliation(s)
- Katharina Dach
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California-Davis, Davis, CA California 95616
| | - Bianca Yaghoobi
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California-Davis, Davis, CA California 95616
| | - Martin R Schmuck
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California-Davis, Davis, CA California 95616
| | - Dennis R Carty
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California-Davis, Davis, CA California 95616
| | - Kelly M Morales
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California-Davis, Davis, CA California 95616
| | - Pamela J Lein
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California-Davis, Davis, CA California 95616
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Behl M, Ryan K, Hsieh JH, Parham F, Shapiro AJ, Collins BJ, Sipes NS, Birnbaum LS, Bucher JR, Foster PMD, Walker NJ, Paules RS, Tice RR. Screening for Developmental Neurotoxicity at the National Toxicology Program: The Future Is Here. Toxicol Sci 2019; 167:6-14. [PMID: 30496580 DOI: 10.1093/toxsci/kfy278] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The National Toxicology Program (NTP) receives requests to evaluate chemicals with potential to cause adverse health effects, including developmental neurotoxicity (DNT). Some recent requests have included classes of chemicals such as flame retardants, polycyclic aromatic compounds, perfluoroalkyl substances, and bisphenol A analogs with approximately 20-50 compounds per class, many of which include commercial mixtures. However, all the compounds within a class cannot be tested using traditional DNT animal testing guideline studies due to resource and time limitations. Hence, a rapid and biologically relevant screening approach is required to prioritize compounds for further in vivo testing. Because neurodevelopment is a complex process involving multiple distinct cellular processes, one assay will unlikely address the complexity. Hence, the NTP sought to characterize a battery of in vitro and alternative animal assays to quantify chemical effects on a variety of neurodevelopmental processes. A culmination of this effort resulted in a NTP-hosted collaborative project with approximately 40 participants spanning across domains of academia, industry, government, and regulatory agencies; collaborators presented data on cell-based assays and alternative animal models that was generated using a targeted set of compounds provided by the NTP. The NTP analyzed the assay results using benchmark concentration (BMC) modeling to be able to compare results across the divergent assays. The results were shared with the contributing researchers on a private web application during the workshop, and are now publicly available. This article highlights the overview and goals of the project, and describes the NTP's approach in creating the chemical library, development of NTPs data analysis strategy, and the structure of the web application. Finally, we discuss key issues with emphasis on the utility of this approach, and knowledge gaps that need to be addressed for its use in regulatory decision making.
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Affiliation(s)
- Mamta Behl
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709
| | - Kristen Ryan
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709
| | - Jui-Hua Hsieh
- Kelly Government Solutions, Durham, North Carolina 27709
| | - Frederick Parham
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709
| | - Andrew J Shapiro
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709
| | - Bradley J Collins
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709
| | - Nisha S Sipes
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709
| | - Linda S Birnbaum
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709
| | - John R Bucher
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709
| | - Paul M D Foster
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709
| | - Nigel J Walker
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709
| | - Richard S Paules
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709
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35
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Koiwa J, Shiromizu T, Adachi Y, Ikejiri M, Nakatani K, Tanaka T, Nishimura Y. Generation of a Triple-Transgenic Zebrafish Line for Assessment of Developmental Neurotoxicity during Neuronal Differentiation. Pharmaceuticals (Basel) 2019; 12:E145. [PMID: 31554324 PMCID: PMC6958351 DOI: 10.3390/ph12040145] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 09/19/2019] [Accepted: 09/22/2019] [Indexed: 12/15/2022] Open
Abstract
: The developing brain is extremely sensitive to many chemicals. Exposure to neurotoxicants during development has been implicated in various neuropsychiatric and neurological disorders, including autism spectrum disorders and schizophrenia. Various screening methods have been used to assess the developmental neurotoxicity (DNT) of chemicals, with most assays focusing on cell viability, apoptosis, proliferation, migration, neuronal differentiation, and neuronal network formation. However, assessment of toxicity during progenitor cell differentiation into neurons, astrocytes, and oligodendrocytes often requires immunohistochemistry, which is a reliable but labor-intensive and time-consuming assay. Here, we report the development of a triple-transgenic zebrafish line that expresses distinct fluorescent proteins in neurons (Cerulean), astrocytes (mCherry), and oligodendrocytes (mCitrine), which can be used to detect DNT during neuronal differentiation. Using in vivo fluorescence microscopy, we could detect DNT by 6 of the 10 neurotoxicants tested after exposure to zebrafish from 12 h to 5 days' post-fertilization. Moreover, the chemicals could be clustered into three main DNT groups based on the fluorescence pattern: (i) inhibition of neuron and oligodendrocyte differentiation and stimulation of astrocyte differentiation; (ii) inhibition of neuron and oligodendrocyte differentiation; and (iii) inhibition of neuron and astrocyte differentiation, which suggests that reporter expression reflects the toxicodynamics of the chemicals. Thus, the triple-transgenic zebrafish line developed here may be a useful tool to assess DNT during neuronal differentiation.
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Affiliation(s)
- Junko Koiwa
- Department of Integrative Pharmacology, Mie University Graduate School of Medicine, Tsu, Mie 514-8507, Japan.
| | - Takashi Shiromizu
- Department of Integrative Pharmacology, Mie University Graduate School of Medicine, Tsu, Mie 514-8507, Japan.
| | - Yuka Adachi
- Department of Integrative Pharmacology, Mie University Graduate School of Medicine, Tsu, Mie 514-8507, Japan.
| | - Makoto Ikejiri
- Department of Central Laboratory, Mie University Hospital, Tsu, Mie 514-8507, Japan.
| | - Kaname Nakatani
- Department of Genomic Medicine, Mie University Hospital, Tsu, Mie 514-8507, Japan.
| | - Toshio Tanaka
- Department of Systems Pharmacology, Mie University Graduate School of Medicine, Tsu, Mie 514-8507, Japan.
| | - Yuhei Nishimura
- Department of Integrative Pharmacology, Mie University Graduate School of Medicine, Tsu, Mie 514-8507, Japan.
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36
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Spinu N, Bal-Price A, Cronin MTD, Enoch SJ, Madden JC, Worth AP. Development and analysis of an adverse outcome pathway network for human neurotoxicity. Arch Toxicol 2019; 93:2759-2772. [DOI: 10.1007/s00204-019-02551-1] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Accepted: 08/14/2019] [Indexed: 12/21/2022]
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37
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Lanzoni A, Castoldi AF, Kass GE, Terron A, De Seze G, Bal-Price A, Bois FY, Delclos KB, Doerge DR, Fritsche E, Halldorsson T, Kolossa-Gehring M, Hougaard Bennekou S, Koning F, Lampen A, Leist M, Mantus E, Rousselle C, Siegrist M, Steinberg P, Tritscher A, Van de Water B, Vineis P, Walker N, Wallace H, Whelan M, Younes M. Advancing human health risk assessment. EFSA J 2019; 17:e170712. [PMID: 32626449 PMCID: PMC7015480 DOI: 10.2903/j.efsa.2019.e170712] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The current/traditional human health risk assessment paradigm is challenged by recent scientific and technical advances, and ethical demands. The current approach is considered too resource intensive, is not always reliable, can raise issues of reproducibility, is mostly animal based and does not necessarily provide an understanding of the underlying mechanisms of toxicity. From an ethical and scientific viewpoint, a paradigm shift is required to deliver testing strategies that enable reliable, animal-free hazard and risk assessments, which are based on a mechanistic understanding of chemical toxicity and make use of exposure science and epidemiological data. This shift will require a new philosophy, new data, multidisciplinary expertise and more flexible regulations. Re-engineering of available data is also deemed necessary as data should be accessible, readable, interpretable and usable. Dedicated training to build the capacity in terms of expertise is necessary, together with practical resources allocated to education. The dialogue between risk assessors, risk managers, academia and stakeholders should be promoted further to understand scientific and societal needs. Genuine interest in taking risk assessment forward should drive the change and should be supported by flexible funding. This publication builds upon presentations made and discussions held during the break-out session 'Advancing risk assessment science - Human health' at EFSA's third Scientific Conference 'Science, Food and Society' (Parma, Italy, 18-21 September 2018).
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Affiliation(s)
| | | | | | | | | | | | - Frédéric Y Bois
- French National Institute for Industrial Environment and Risks FR
| | - K Barry Delclos
- National Center for Toxicological Research US Food and Drug Administration USA
| | - Daniel R Doerge
- National Center for Toxicological Research US Food and Drug Administration USA
| | - Ellen Fritsche
- Leibniz Research Institute for Environmental Medicine DE
| | | | | | | | | | | | | | - Ellen Mantus
- The National Academies of Sciences, Engineering, and Medicine USA
| | | | | | | | | | - Bob Van de Water
- Drug Discovery and Safety Leiden Academic Centre for Drug Research Leiden University NL
| | | | - Nigel Walker
- National Toxicology Program/National Institute of Environmental Health Sciences USA
| | - Heather Wallace
- Institute of Medical Sciences University of Aberdeen Scotland UK
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38
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Ash PEA, Dhawan U, Boudeau S, Lei S, Carlomagno Y, Knobel M, Al Mohanna LFA, Boomhower SR, Newland MC, Sherr DH, Wolozin B. Heavy Metal Neurotoxicants Induce ALS-Linked TDP-43 Pathology. Toxicol Sci 2019; 167:105-115. [PMID: 30371865 PMCID: PMC6317426 DOI: 10.1093/toxsci/kfy267] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Heavy metals, such as lead, mercury, and selenium, have been epidemiologically linked with a risk of ALS, but a molecular mechanism proving the connection has not been shown. A screen of putative developmental neurotoxins demonstrated that heavy metals (lead, mercury, and tin) trigger accumulation of TDP-43 into nuclear granules with concomitant loss of diffuse nuclear TDP-43. Lead (Pb) and methyl mercury (MeHg) disrupt the homeostasis of TDP-43 in neurons, resulting in increased levels of transcript and increased splicing activity of TDP-43. TDP-43 homeostasis is tightly regulated, and positively or negatively altering its splicing-suppressive activity has been shown to be deleterious to neurons. These changes are associated with the liquid-liquid phase separation of TDP-43 into nuclear bodies. We show that lead directly facilitates phase separation of TDP-43 in a dose-dependent manner in vitro, possibly explaining the means by which lead treatment results in neuronal nuclear granules. Metal toxicants also triggered the accumulation of insoluble TDP-43 in cultured cells and in the cortices of exposed mice. These results provide novel evidence of a direct mechanistic link between heavy metals, which are a commonly cited environmental risk of ALS, and molecular changes in TDP-43, the primary pathological protein accumulating in ALS.
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Affiliation(s)
- Peter E A Ash
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, Massachusetts 02118
| | - Uma Dhawan
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, Massachusetts 02118
- Department of Biomedical Science, Bhaskaracharya College of Applied Sciences, University of Delhi, Delhi 110075, India
| | - Samantha Boudeau
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, Massachusetts 02118
| | - Shuwen Lei
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, Massachusetts 02118
| | - Yari Carlomagno
- Neuroscience Division, Mayo Clinic, Jacksonville, Florida 32224
| | - Mark Knobel
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, Massachusetts 02118
| | - Louloua F A Al Mohanna
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, Massachusetts 02118
| | - Steven R Boomhower
- Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115
| | | | - David H Sherr
- Department of Environmental Health, Boston University School of Public Health
| | - Benjamin Wolozin
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, Massachusetts 02118
- Department of Neurology, Boston University School of Medicine, Boston, Massachusetts 02118
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39
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Bal-Price A, Pistollato F, Sachana M, Bopp SK, Munn S, Worth A. Strategies to improve the regulatory assessment of developmental neurotoxicity (DNT) using in vitro methods. Toxicol Appl Pharmacol 2018; 354:7-18. [PMID: 29476865 PMCID: PMC6095942 DOI: 10.1016/j.taap.2018.02.008] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 02/05/2018] [Accepted: 02/13/2018] [Indexed: 01/23/2023]
Abstract
Currently, the identification of chemicals that have the potential to induce developmental neurotoxicity (DNT) is based on animal testing. Since at the regulatory level, systematic testing of DNT is not a standard requirement within the EU or USA chemical legislation safety assessment, DNT testing is only performed in higher tiered testing triggered based on chemical structure activity relationships or evidence of neurotoxicity in systemic acute or repeated dose toxicity studies. However, these triggers are rarely used and, in addition, do not always serve as reliable indicators of DNT, as they are generally based on observations in adult rodents. Therefore, there is a pressing need for developing alternative methodologies that can reliably support identification of DNT triggers, and more rapidly and cost-effectively support the identification and characterization of chemicals with DNT potential. We propose to incorporate mechanistic knowledge and data derived from in vitro studies to support various regulatory applications including: (a) the identification of potential DNT triggers, (b) initial chemical screening and prioritization, (c) hazard identification and characterization, (d) chemical biological grouping, and (e) assessment of exposure to chemical mixtures. Ideally, currently available cellular neuronal/glial models derived from human induced pluripotent stem cells (hiPSCs) should be used as they allow evaluation of chemical impacts on key neurodevelopmental processes, by reproducing different windows of exposure during human brain development. A battery of DNT in vitro test methods derived from hiPSCs could generate valuable mechanistic data, speeding up the evaluation of thousands of compounds present in industrial, agricultural and consumer products that lack safety data on DNT potential.
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Affiliation(s)
- Anna Bal-Price
- European Commission, Joint Research Centre (JRC), Ispra, Italy.
| | | | - Magdalini Sachana
- Organisation for Economic Co-operation and Development (OECD), 2 rue André Pascal, 75775 Paris, Cedex 16, France
| | | | - Sharon Munn
- European Commission, Joint Research Centre (JRC), Ispra, Italy
| | - Andrew Worth
- European Commission, Joint Research Centre (JRC), Ispra, Italy
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40
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Saili KS, Zurlinden TJ, Schwab AJ, Silvin A, Baker NC, Hunter ES, Ginhoux F, Knudsen TB. Blood-brain barrier development: Systems modeling and predictive toxicology. Birth Defects Res 2018; 109:1680-1710. [PMID: 29251840 DOI: 10.1002/bdr2.1180] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Accepted: 11/12/2017] [Indexed: 01/17/2023]
Abstract
The blood-brain barrier (BBB) serves as a gateway for passage of drugs, chemicals, nutrients, metabolites, and hormones between vascular and neural compartments in the brain. Here, we review BBB development with regard to the microphysiology of the neurovascular unit (NVU) and the impact of BBB disruption on brain development. Our focus is on modeling these complex systems. Extant in silico models are available as tools to predict the probability of drug/chemical passage across the BBB; in vitro platforms for high-throughput screening and high-content imaging provide novel data streams for profiling chemical-biological interactions; and engineered human cell-based microphysiological systems provide empirical models with which to investigate the dynamics of NVU function. Computational models are needed that bring together kinetic and dynamic aspects of NVU function across gestation and under various physiological and toxicological scenarios. This integration will inform adverse outcome pathways to reduce uncertainty in translating in vitro data and in silico models for use in risk assessments that aim to protect neurodevelopmental health.
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Affiliation(s)
- Katerine S Saili
- National Center for Computational Toxicology (NCCT); U.S. Environmental Protection Agency, Office of Research and Development, Research Triangle Park, North Carolina 27711
| | - Todd J Zurlinden
- National Center for Computational Toxicology (NCCT); U.S. Environmental Protection Agency, Office of Research and Development, Research Triangle Park, North Carolina 27711
| | - Andrew J Schwab
- National Health and Environmental Effects Research Laboratory (NHEERL), U.S. Environmental Protection Agency, Office of Research and Development, Research Triangle Park, North Carolina 27711
| | - Aymeric Silvin
- Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), 138648, Singapore
| | - Nancy C Baker
- Leidos, contractor to NCCT, Research Triangle Park, North Carolina 27711
| | - E Sidney Hunter
- National Health and Environmental Effects Research Laboratory (NHEERL), U.S. Environmental Protection Agency, Office of Research and Development, Research Triangle Park, North Carolina 27711
| | - Florent Ginhoux
- Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), 138648, Singapore
| | - Thomas B Knudsen
- National Center for Computational Toxicology (NCCT); U.S. Environmental Protection Agency, Office of Research and Development, Research Triangle Park, North Carolina 27711
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41
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Odawara A, Matsuda N, Ishibashi Y, Yokoi R, Suzuki I. Toxicological evaluation of convulsant and anticonvulsant drugs in human induced pluripotent stem cell-derived cortical neuronal networks using an MEA system. Sci Rep 2018; 8:10416. [PMID: 29991696 PMCID: PMC6039442 DOI: 10.1038/s41598-018-28835-7] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 07/02/2018] [Indexed: 12/14/2022] Open
Abstract
Functional evaluation assays using human induced pluripotent stem cell (hiPSC)-derived neurons can predict the convulsion toxicity of new drugs and the neurological effects of antiepileptic drugs. However, differences in responsiveness depending on convulsant type and antiepileptic drugs, and an evaluation index capable of comparing in vitro responses with in vivo responses are not well known. We observed the difference in synchronized burst patterns in the epileptiform activities induced by pentylentetrazole (PTZ) and 4-aminopryridine (4-AP) with different action mechanisms using multi-electrode arrays (MEAs); we also observed that 100 µM of the antiepileptic drug phenytoin suppressed epileptiform activities induced by PTZ, but increased those induced by 4-AP. To compare in vitro results with in vivo convulsive responses, frequency analysis of below 250 Hz, excluding the spike component, was performed. The in vivo convulsive firing enhancement of the high γ wave and β wave component were observed remarkably in in vitro hiPSC-derived neurons with astrocytes in co-culture. MEA measurement of hiPSC-derived neurons in co-culture with astrocytes and our analysis methods, including frequency analysis, appear effective for predicting convulsion toxicity, side effects, and their mechanism of action as well as the comparison of convulsions induced in vivo.
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Affiliation(s)
- A Odawara
- Department of Electronics, Graduate School of Engineering, Tohoku Institute of Technology, 35-1 Yagiyama Kasumicho, Taihaku-ku, Sendai, Miyagi, 982-8577, Japan.,Advanced Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi, 982-8577, Japan.,Japan Society for the Promotion of Science, Tokyo, Japan
| | - N Matsuda
- Department of Electronics, Graduate School of Engineering, Tohoku Institute of Technology, 35-1 Yagiyama Kasumicho, Taihaku-ku, Sendai, Miyagi, 982-8577, Japan
| | - Y Ishibashi
- Department of Electronics, Graduate School of Engineering, Tohoku Institute of Technology, 35-1 Yagiyama Kasumicho, Taihaku-ku, Sendai, Miyagi, 982-8577, Japan
| | - R Yokoi
- Department of Electronics, Graduate School of Engineering, Tohoku Institute of Technology, 35-1 Yagiyama Kasumicho, Taihaku-ku, Sendai, Miyagi, 982-8577, Japan
| | - I Suzuki
- Department of Electronics, Graduate School of Engineering, Tohoku Institute of Technology, 35-1 Yagiyama Kasumicho, Taihaku-ku, Sendai, Miyagi, 982-8577, Japan. .,iPS-non-Clinical Experiments for Nervous System (iNCENS) Project, Kanagawa, Japan. .,Consortium for Safety Assessment using Human iPS Cells (CSAHi), Kanagawa, Japan.
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42
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Bal-Price A, Hogberg HT, Crofton KM, Daneshian M, FitzGerald RE, Fritsche E, Heinonen T, Hougaard Bennekou S, Klima S, Piersma AH, Sachana M, Shafer TJ, Terron A, Monnet-Tschudi F, Viviani B, Waldmann T, Westerink RHS, Wilks MF, Witters H, Zurich MG, Leist M. Recommendation on test readiness criteria for new approach methods in toxicology: Exemplified for developmental neurotoxicity. ALTEX-ALTERNATIVES TO ANIMAL EXPERIMENTATION 2018; 35:306-352. [PMID: 29485663 DOI: 10.14573/altex.1712081] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 01/29/2018] [Indexed: 01/06/2023]
Abstract
Multiple non-animal-based test methods have never been formally validated. In order to use such new approach methods (NAMs) in a regulatory context, criteria to define their readiness are necessary. The field of developmental neurotoxicity (DNT) testing is used to exemplify the application of readiness criteria. The costs and number of untested chemicals are overwhelming for in vivo DNT testing. Thus, there is a need for inexpensive, high-throughput NAMs, to obtain initial information on potential hazards, and to allow prioritization for further testing. A background on the regulatory and scientific status of DNT testing is provided showing different types of test readiness levels, depending on the intended use of data from NAMs. Readiness criteria, compiled during a stakeholder workshop, uniting scientists from academia, industry and regulatory authorities are presented. An important step beyond the listing of criteria, was the suggestion for a preliminary scoring scheme. On this basis a (semi)-quantitative analysis process was assembled on test readiness of 17 NAMs with respect to various uses (e.g. prioritization/screening, risk assessment). The scoring results suggest that several assays are currently at high readiness levels. Therefore, suggestions are made on how DNT NAMs may be assembled into an integrated approach to testing and assessment (IATA). In parallel, the testing state in these assays was compiled for more than 1000 compounds. Finally, a vision is presented on how further NAM development may be guided by knowledge of signaling pathways necessary for brain development, DNT pathophysiology, and relevant adverse outcome pathways (AOP).
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Affiliation(s)
- Anna Bal-Price
- European Commission, Joint Research Centre (EC JRC), Ispra (VA), Italy
| | - Helena T Hogberg
- Center for Alternatives to Animal Testing (CAAT), Johns Hopkins University, Baltimore, MD, USA
| | - Kevin M Crofton
- National Centre for Computational Toxicology, US EPA, RTP, Washington, NC, USA
| | - Mardas Daneshian
- Center for Alternatives to Animal Testing, CAAT-Europe, University of Konstanz, Konstanz, Germany
| | - Rex E FitzGerald
- Swiss Centre for Human Applied Toxicology, SCAHT, University of Basle, Switzerland
| | - Ellen Fritsche
- IUF - Leibniz Research Institute for Environmental Medicine & Heinrich-Heine-University, Düsseldorf, Germany
| | - Tuula Heinonen
- Finnish Centre for Alternative Methods (FICAM), University of Tampere, Tampere, Finland
| | | | - Stefanie Klima
- In vitro Toxicology and Biomedicine, Department of Biology, University of Konstanz, Konstanz, Germany
| | - Aldert H Piersma
- RIVM, National Institute for Public Health and the Environment, Bilthoven, and Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands
| | - Magdalini Sachana
- Organisation for Economic Co-operation and Development (OECD), Paris, France
| | - Timothy J Shafer
- National Centre for Computational Toxicology, US EPA, RTP, Washington, NC, USA
| | | | - Florianne Monnet-Tschudi
- Swiss Centre for Human Applied Toxicology, SCAHT, University of Basle, Switzerland.,Department of Physiology, University of Lausanne, Lausanne, Switzerland
| | - Barbara Viviani
- Department of Pharmacological and Biomolecular Sciences, University of Milan, Italy
| | - Tanja Waldmann
- In vitro Toxicology and Biomedicine, Department of Biology, University of Konstanz, Konstanz, Germany
| | - Remco H S Westerink
- Neurotoxicology Research Group, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Martin F Wilks
- Swiss Centre for Human Applied Toxicology, SCAHT, University of Basle, Switzerland
| | - Hilda Witters
- VITO, Flemish Institute for Technological Research, Unit Environmental Risk and Health, Mol, Belgium
| | - Marie-Gabrielle Zurich
- Swiss Centre for Human Applied Toxicology, SCAHT, University of Basle, Switzerland.,Department of Physiology, University of Lausanne, Lausanne, Switzerland
| | - Marcel Leist
- Center for Alternatives to Animal Testing, CAAT-Europe, University of Konstanz, Konstanz, Germany.,In vitro Toxicology and Biomedicine, Department of Biology, University of Konstanz, Konstanz, Germany
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43
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Fritsche E, Grandjean P, Crofton KM, Aschner M, Goldberg A, Heinonen T, Hessel EVS, Hogberg HT, Bennekou SH, Lein PJ, Leist M, Mundy WR, Paparella M, Piersma AH, Sachana M, Schmuck G, Solecki R, Terron A, Monnet-Tschudi F, Wilks MF, Witters H, Zurich MG, Bal-Price A. Consensus statement on the need for innovation, transition and implementation of developmental neurotoxicity (DNT) testing for regulatory purposes. Toxicol Appl Pharmacol 2018; 354:3-6. [PMID: 29447839 PMCID: PMC6097873 DOI: 10.1016/j.taap.2018.02.004] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 02/09/2018] [Accepted: 02/10/2018] [Indexed: 01/15/2023]
Abstract
This consensus statement voices the agreement of scientific stakeholders from regulatory agencies, academia and industry that a new framework needs adopting for assessment of chemicals with the potential to disrupt brain development. An increased prevalence of neurodevelopmental disorders in children has been observed that cannot solely be explained by genetics and recently pre- and postnatal exposure to environmental chemicals has been suspected as a causal factor. There is only very limited information on neurodevelopmental toxicity, leaving thousands of chemicals, that are present in the environment, with high uncertainty concerning their developmental neurotoxicity (DNT) potential. Closing this data gap with the current test guideline approach is not feasible, because the in vivo bioassays are far too resource-intensive concerning time, money and number of animals. A variety of in vitro methods are now available, that have the potential to close this data gap by permitting mode-of-action-based DNT testing employing human stem cells-derived neuronal/glial models. In vitro DNT data together with in silico approaches will in the future allow development of predictive models for DNT effects. The ultimate application goals of these new approach methods for DNT testing are their usage for different regulatory purposes. An increased prevalence of neurodevelopmental disorders in children is observed. There is very limited information on neurodevelopmental toxicity (DNT) induced by environmental chemicals. A new framework is required for assessment of chemicals with the potential to disrupt brain development. In vitro DNT data together with in silico approaches should be used for regulatory purposes.
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Affiliation(s)
- Ellen Fritsche
- IUF - Leibniz Research Institute for Environmental Medicine, Duesseldorf, Germany
| | - Philippe Grandjean
- University of Southern Denmark, Harvard T.H. Chan School of Public Health, USA
| | | | | | - Alan Goldberg
- Bloomberg School of Public Health, Founding Director (Emeritus) of Center for Alternatives to Animal Testing (CAAT), Johns Hopkins University, Baltimore, USA; Global Food Ethics, Johns Hopkins University, Baltimore, USA
| | - Tuula Heinonen
- Finnish Centre for Alternative Methods (FICAM), University of Tampere, Tampere, Finland
| | - Ellen V S Hessel
- National Institute for Public Health and the Environment, RIVM Center for Health Protection, Bilthoven, Netherlands
| | - Helena T Hogberg
- Centre for Alternatives to Animal Testing (CAAT), Johns Hopkins University, Baltimore, USA
| | | | - Pamela J Lein
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California Davis, Davis, USA
| | - Marcel Leist
- CAAT - Centre for Alternatives to Animal Testing, University of Konstanz, Konstanz, Germany
| | | | | | - Aldert H Piersma
- RIVM Center for Health Protection, Bilthoven and Institute for Risk Assessment Sciences, Utrecht University, Utrecht, Netherlands
| | - Magdalini Sachana
- Organisation for Economic Co-operation and Development (OECD), Paris, France
| | | | - Roland Solecki
- Federal Institute for Risk Assessment (BfR), Berlin, Germany
| | | | | | - Martin F Wilks
- SCAHT - Swiss Centre for Applied Human Toxicology, University of Basel, Basel, Switzerland
| | - Hilda Witters
- VITO, Flemish Institute for Technological Research, Unit Environmental Risk and Health, Belgium
| | | | - Anna Bal-Price
- European Commission -DG Joint Research Centre (JRC), Ispra, Italy.
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44
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Legradi JB, Di Paolo C, Kraak MHS, van der Geest HG, Schymanski EL, Williams AJ, Dingemans MML, Massei R, Brack W, Cousin X, Begout ML, van der Oost R, Carion A, Suarez-Ulloa V, Silvestre F, Escher BI, Engwall M, Nilén G, Keiter SH, Pollet D, Waldmann P, Kienle C, Werner I, Haigis AC, Knapen D, Vergauwen L, Spehr M, Schulz W, Busch W, Leuthold D, Scholz S, vom Berg CM, Basu N, Murphy CA, Lampert A, Kuckelkorn J, Grummt T, Hollert H. An ecotoxicological view on neurotoxicity assessment. ENVIRONMENTAL SCIENCES EUROPE 2018; 30:46. [PMID: 30595996 PMCID: PMC6292971 DOI: 10.1186/s12302-018-0173-x] [Citation(s) in RCA: 139] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 10/31/2018] [Indexed: 05/04/2023]
Abstract
The numbers of potential neurotoxicants in the environment are raising and pose a great risk for humans and the environment. Currently neurotoxicity assessment is mostly performed to predict and prevent harm to human populations. Despite all the efforts invested in the last years in developing novel in vitro or in silico test systems, in vivo tests with rodents are still the only accepted test for neurotoxicity risk assessment in Europe. Despite an increasing number of reports of species showing altered behaviour, neurotoxicity assessment for species in the environment is not required and therefore mostly not performed. Considering the increasing numbers of environmental contaminants with potential neurotoxic potential, eco-neurotoxicity should be also considered in risk assessment. In order to do so novel test systems are needed that can cope with species differences within ecosystems. In the field, online-biomonitoring systems using behavioural information could be used to detect neurotoxic effects and effect-directed analyses could be applied to identify the neurotoxicants causing the effect. Additionally, toxic pressure calculations in combination with mixture modelling could use environmental chemical monitoring data to predict adverse effects and prioritize pollutants for laboratory testing. Cheminformatics based on computational toxicological data from in vitro and in vivo studies could help to identify potential neurotoxicants. An array of in vitro assays covering different modes of action could be applied to screen compounds for neurotoxicity. The selection of in vitro assays could be guided by AOPs relevant for eco-neurotoxicity. In order to be able to perform risk assessment for eco-neurotoxicity, methods need to focus on the most sensitive species in an ecosystem. A test battery using species from different trophic levels might be the best approach. To implement eco-neurotoxicity assessment into European risk assessment, cheminformatics and in vitro screening tests could be used as first approach to identify eco-neurotoxic pollutants. In a second step, a small species test battery could be applied to assess the risks of ecosystems.
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Affiliation(s)
- J. B. Legradi
- Institute for Environmental Research, Department of Ecosystem Analysis, ABBt–Aachen Biology and Biotechnology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
- Environment and Health, VU University, 1081 HV Amsterdam, The Netherlands
| | - C. Di Paolo
- Institute for Environmental Research, Department of Ecosystem Analysis, ABBt–Aachen Biology and Biotechnology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
| | - M. H. S. Kraak
- FAME-Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94248, 1090 GE Amsterdam, The Netherlands
| | - H. G. van der Geest
- FAME-Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94248, 1090 GE Amsterdam, The Netherlands
| | - E. L. Schymanski
- Luxembourg Centre for Systems Biomedicine (LCSB), University of Luxembourg, 6 Avenue du Swing, 4367 Belvaux, Luxembourg
| | - A. J. Williams
- National Center for Computational Toxicology, Office of Research and Development, U.S. Environmental Protection Agency, 109 T.W. Alexander Dr., Research Triangle Park, NC 27711 USA
| | - M. M. L. Dingemans
- KWR Watercycle Research Institute, Groningenhaven 7, 3433 PE Nieuwegein, The Netherlands
| | - R. Massei
- Department Effect-Directed Analysis, Helmholtz Centre for Environmental Research-UFZ, Permoserstr. 15, Leipzig, Germany
| | - W. Brack
- Department Effect-Directed Analysis, Helmholtz Centre for Environmental Research-UFZ, Permoserstr. 15, Leipzig, Germany
| | - X. Cousin
- Ifremer, UMR MARBEC, Laboratoire Adaptation et Adaptabilités des Animaux et des Systèmes, Route de Maguelone, 34250 Palavas-les-Flots, France
- INRA, UMR GABI, INRA, AgroParisTech, Domaine de Vilvert, Batiment 231, 78350 Jouy-en-Josas, France
| | - M.-L. Begout
- Ifremer, Laboratoire Ressources Halieutiques, Place Gaby Coll, 17137 L’Houmeau, France
| | - R. van der Oost
- Department of Technology, Research and Engineering, Waternet Institute for the Urban Water Cycle, Amsterdam, The Netherlands
| | - A. Carion
- Laboratory of Evolutionary and Adaptive Physiology, Institute of Life, Earth and Environment, University of Namur, 5000 Namur, Belgium
| | - V. Suarez-Ulloa
- Laboratory of Evolutionary and Adaptive Physiology, Institute of Life, Earth and Environment, University of Namur, 5000 Namur, Belgium
| | - F. Silvestre
- Laboratory of Evolutionary and Adaptive Physiology, Institute of Life, Earth and Environment, University of Namur, 5000 Namur, Belgium
| | - B. I. Escher
- Department of Cell Toxicology, Helmholtz Centre for Environmental Research-UFZ, Permoserstr. 15, 04318 Leipzig, Germany
- Eberhard Karls University Tübingen, Environmental Toxicology, Center for Applied Geosciences, 72074 Tübingen, Germany
| | - M. Engwall
- MTM Research Centre, School of Science and Technology, Örebro University, Fakultetsgatan 1, 70182 Örebro, Sweden
| | - G. Nilén
- MTM Research Centre, School of Science and Technology, Örebro University, Fakultetsgatan 1, 70182 Örebro, Sweden
| | - S. H. Keiter
- MTM Research Centre, School of Science and Technology, Örebro University, Fakultetsgatan 1, 70182 Örebro, Sweden
| | - D. Pollet
- Faculty of Chemical Engineering and Biotechnology, University of Applied Sciences Darmstadt, Stephanstrasse 7, 64295 Darmstadt, Germany
| | - P. Waldmann
- Faculty of Chemical Engineering and Biotechnology, University of Applied Sciences Darmstadt, Stephanstrasse 7, 64295 Darmstadt, Germany
| | - C. Kienle
- Swiss Centre for Applied Ecotoxicology Eawag-EPFL, Überlandstrasse 133, 8600 Dübendorf, Switzerland
| | - I. Werner
- Swiss Centre for Applied Ecotoxicology Eawag-EPFL, Überlandstrasse 133, 8600 Dübendorf, Switzerland
| | - A.-C. Haigis
- Institute for Environmental Research, Department of Ecosystem Analysis, ABBt–Aachen Biology and Biotechnology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
| | - D. Knapen
- Zebrafishlab, Veterinary Physiology and Biochemistry, University of Antwerp, Wilrijk, Belgium
| | - L. Vergauwen
- Zebrafishlab, Veterinary Physiology and Biochemistry, University of Antwerp, Wilrijk, Belgium
| | - M. Spehr
- Institute for Biology II, Department of Chemosensation, RWTH Aachen University, Aachen, Germany
| | - W. Schulz
- Zweckverband Landeswasserversorgung, Langenau, Germany
| | - W. Busch
- Department of Bioanalytical Ecotoxicology, UFZ–Helmholtz Centre for Environmental Research, Leipzig, Germany
| | - D. Leuthold
- Department of Bioanalytical Ecotoxicology, UFZ–Helmholtz Centre for Environmental Research, Leipzig, Germany
| | - S. Scholz
- Department of Bioanalytical Ecotoxicology, UFZ–Helmholtz Centre for Environmental Research, Leipzig, Germany
| | - C. M. vom Berg
- Department of Environmental Toxicology, Swiss Federal Institute of Aquatic Science and Technology, Eawag, Dübendorf, 8600 Switzerland
| | - N. Basu
- Faculty of Agricultural and Environmental Sciences, McGill University, Montreal, Canada
| | - C. A. Murphy
- Department of Fisheries and Wildlife, Michigan State University, East Lansing, USA
| | - A. Lampert
- Institute of Physiology (Neurophysiology), Aachen, Germany
| | - J. Kuckelkorn
- Section Toxicology of Drinking Water and Swimming Pool Water, Federal Environment Agency (UBA), Heinrich-Heine-Str. 12, 08645 Bad Elster, Germany
| | - T. Grummt
- Section Toxicology of Drinking Water and Swimming Pool Water, Federal Environment Agency (UBA), Heinrich-Heine-Str. 12, 08645 Bad Elster, Germany
| | - H. Hollert
- Institute for Environmental Research, Department of Ecosystem Analysis, ABBt–Aachen Biology and Biotechnology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
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45
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Nyffeler J, Chovancova P, Dolde X, Holzer AK, Purvanov V, Kindinger I, Kerins A, Higton D, Silvester S, van Vugt-Lussenburg BMA, Glaab E, van der Burg B, Maclennan R, Legler DF, Leist M. A structure-activity relationship linking non-planar PCBs to functional deficits of neural crest cells: new roles for connexins. Arch Toxicol 2017; 92:1225-1247. [PMID: 29164306 DOI: 10.1007/s00204-017-2125-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2017] [Accepted: 11/15/2017] [Indexed: 12/14/2022]
Abstract
Migration of neural crest cells (NCC) is a fundamental developmental process, and test methods to identify interfering toxicants have been developed. By examining cell function endpoints, as in the 'migration-inhibition of NCC (cMINC)' assay, a large number of toxicity mechanisms and protein targets can be covered. However, the key events that lead to the adverse effects of a given chemical or group of related compounds are hard to elucidate. To address this issue, we explored here, whether the establishment of two overlapping structure-activity relationships (SAR)-linking chemical structure on the one hand to a phenotypic test outcome, and on the other hand to a mechanistic endpoint-was useful as strategy to identify relevant toxicity mechanisms. For this purpose, we chose polychlorinated biphenyls (PCB) as a large group of related, but still toxicologically and physicochemically diverse structures. We obtained concentration-dependent data for 26 PCBs in the cMINC assay. Moreover, the test chemicals were evaluated by a new high-content imaging method for their effect on cellular re-distribution of connexin43 and for their capacity to inhibit gap junctions. Non-planar PCBs inhibited NCC migration. The potency (1-10 µM) correlated with the number of ortho-chlorine substituents; non-ortho-chloro (planar) PCBs were non-toxic. The toxicity to NCC partially correlated with gap junction inhibition, while it fully correlated (p < 0.0004) with connexin43 cellular re-distribution. Thus, our double-SAR strategy revealed a mechanistic step tightly linked to NCC toxicity of PCBs. Connexin43 patterns in NCC may be explored as a new endpoint relevant to developmental toxicity screening.
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Affiliation(s)
- Johanna Nyffeler
- In vitro Toxicology and Biomedicine, Department Inaugurated by the Doerenkamp-Zbinden Foundation, University of Konstanz, Universitaetsstr. 10, 78457, Konstanz, Germany.,Research Training Group RTG1331, 78457, Konstanz, Germany
| | - Petra Chovancova
- In vitro Toxicology and Biomedicine, Department Inaugurated by the Doerenkamp-Zbinden Foundation, University of Konstanz, Universitaetsstr. 10, 78457, Konstanz, Germany.,Konstanz Research School Chemical Biology (KoRS-CB), 78457, Konstanz, Germany
| | - Xenia Dolde
- In vitro Toxicology and Biomedicine, Department Inaugurated by the Doerenkamp-Zbinden Foundation, University of Konstanz, Universitaetsstr. 10, 78457, Konstanz, Germany.,Konstanz Research School Chemical Biology (KoRS-CB), 78457, Konstanz, Germany
| | - Anna-Katharina Holzer
- In vitro Toxicology and Biomedicine, Department Inaugurated by the Doerenkamp-Zbinden Foundation, University of Konstanz, Universitaetsstr. 10, 78457, Konstanz, Germany
| | - Vladimir Purvanov
- Biotechnology Institute Thurgau at the University of Konstanz, 8280, Kreuzlingen, Switzerland
| | - Ilona Kindinger
- Biotechnology Institute Thurgau at the University of Konstanz, 8280, Kreuzlingen, Switzerland
| | - Anna Kerins
- Cyprotex Discovery, No 24 Mereside, Alderley Park, Cheshire, SK10 4TG, UK
| | - David Higton
- Cyprotex Discovery, No 24 Mereside, Alderley Park, Cheshire, SK10 4TG, UK
| | - Steve Silvester
- Cyprotex Discovery, No 24 Mereside, Alderley Park, Cheshire, SK10 4TG, UK
| | | | - Enrico Glaab
- Luxembourg Centre for Systems Biomedicine (LCSB), University of Luxembourg, 4362, Esch-sur-Alzette, Luxembourg
| | - Bart van der Burg
- BioDetection Systems bv, Science Park 406, 1098XH, Amsterdam, The Netherlands
| | - Richard Maclennan
- Cyprotex Discovery, No 24 Mereside, Alderley Park, Cheshire, SK10 4TG, UK
| | - Daniel F Legler
- Research Training Group RTG1331, 78457, Konstanz, Germany.,Konstanz Research School Chemical Biology (KoRS-CB), 78457, Konstanz, Germany.,Biotechnology Institute Thurgau at the University of Konstanz, 8280, Kreuzlingen, Switzerland
| | - Marcel Leist
- In vitro Toxicology and Biomedicine, Department Inaugurated by the Doerenkamp-Zbinden Foundation, University of Konstanz, Universitaetsstr. 10, 78457, Konstanz, Germany. .,Research Training Group RTG1331, 78457, Konstanz, Germany. .,Konstanz Research School Chemical Biology (KoRS-CB), 78457, Konstanz, Germany.
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46
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Bond GG, Dietrich DR. Human cost burden of exposure to endocrine disrupting chemicals. A critical review. Arch Toxicol 2017; 91:2745-2762. [PMID: 28528477 DOI: 10.1007/s00204-017-1985-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Accepted: 05/08/2017] [Indexed: 01/01/2023]
Abstract
Recently published papers have alleged that exposures to endocrine disrupting chemicals (EDCs) are causing substantial disease burdens in the EU and US and are consequently costing society hundreds of billions of dollars annually. To date, these cost estimates have not undergone adequate scientific scrutiny, but nevertheless are being used aggressively in advocacy campaigns in an attempt to fundamentally change how chemicals are tested, evaluated and regulated. Consequently, we critically evaluated the underlying methodology and assumptions employed by the chief architects of the disease burden cost estimates. Since the vast majority of their assigned disease burden costs are driven by the assumption that "loss of IQ" and "increased prevalence of intellectual disability" are caused by exposures to organophosphate pesticides (OPPs) and brominated flame retardants (PBDEs), we have taken special care in describing and evaluating the underlying toxicology and epidemiology evidence that was relied upon. Unfortunately, our review uncovered substantial flaws in the approach taken and the conclusions that were drawn. Indeed, the authors of these papers assumed causal relationships between putative exposures to EDCs and selected diseases, i.e., "loss of IQ" and "increased prevalence of intellectual disability", despite not having established them via a thorough evaluation of the strengths and weaknesses of the underlying animal toxicology and human epidemiology evidence. Consequently, the assigned disease burden costs are highly speculative and should not be considered in the weight of evidence approach underlying any serious policy discussions serving to protect the public and regulate chemicals considered as EDCs.
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Affiliation(s)
| | - Daniel R Dietrich
- Human and Environmental Toxicology, University of Konstanz, Constance, Germany
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Combination of multiple neural crest migration assays to identify environmental toxicants from a proof-of-concept chemical library. Arch Toxicol 2017; 91:3613-3632. [PMID: 28477266 DOI: 10.1007/s00204-017-1977-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2016] [Accepted: 04/26/2017] [Indexed: 12/18/2022]
Abstract
Many in vitro tests have been developed to screen for potential neurotoxicity. However, only few cell function-based tests have been used for comparative screening, and thus experience is scarce on how to confirm and evaluate screening hits. We addressed these questions for the neural crest cell migration test (cMINC). After an initial screen, a hit follow-up strategy was devised. A library of 75 compounds plus internal controls (NTP80-list), assembled by the National Toxicology Program of the USA (NTP) was used. It contained some known classes of (developmental) neurotoxic compounds. The primary screen yielded 23 confirmed hits, which comprised ten flame retardants, seven pesticides and six drug-like compounds. Comparison of concentration-response curves for migration and viability showed that all hits were specific. The extent to which migration was inhibited was 25-90%, and two organochlorine pesticides (DDT, heptachlor) were most efficient. In the second part of this study, (1) the cMINC assay was repeated under conditions that prevent proliferation; (2) a transwell migration assay was used as a different type of migration assay; (3) cells were traced to assess cell speed. Some toxicants had largely varying effects between assays, but each hit was confirmed in at least one additional test. This comparative study allows an estimate on how confidently the primary hits from a cell function-based screen can be considered as toxicants disturbing a key neurodevelopmental process. Testing of the NTP80-list in more assays will be highly interesting to assemble a test battery and to build prediction models for developmental toxicity.
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Potential mechanisms of development-dependent adverse effects of the herbicide paraquat in 3D rat brain cell cultures. Neurotoxicology 2017; 60:116-124. [PMID: 28467894 DOI: 10.1016/j.neuro.2017.04.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 04/26/2017] [Accepted: 04/27/2017] [Indexed: 11/23/2022]
Abstract
Exposure to environmental toxicants during vulnerable windows of brain development is suspected to raise the prevalence for neurological dysfunctions at later stages in life. Differentiation processes and changes in morphology, as well as a lack of physiological barriers, might be reasons that render a developing brain more susceptible to neurotoxicants than an adult. However, also the intrinsic capacity of cells to combat toxicant induced cellular stress might differ between the immature- and mature brain. In order to study whether this intrinsic protection capacity differs between immature and maturated brain cells we chose to study the maturation-dependent adverse effects of the known neurotoxicant Paraquat Dichloride (PQ) in 3D rat brain cell cultures. This in vitro system consists of the major brain cell types - neurons, astrocytes, oligodendrocytes and microglia - and over the time in vitro cultured cells undergo differentiation and maturation into a tissue-like organization. PQ was applied repeatedly over ten days in the sub-micromolar range, and effects were evaluated on neurons and glial cells. We observed that despite a higher PQ-uptake in mature cultures, PQ-induced adverse effects on glutamatergic-, GABAergic- and dopaminergic neurons, as assessed by gene expression and enzymatic activity, were more pronounced in immature cultures. This was associated with a stronger astrogliosis in immature- as compared to mature cultures, as well as perturbations of the glutathione-mediated defense against oxidative stress. Furthermore we observed evidence of microglial activation only in mature cultures, whereas immature cultures appeared to down-regulate markers for neuroprotective M2-microglial phenotype upon PQ-exposure. Taken together our results indicate that immature brain cell cultures have less intrinsic capacity to cope with cellular stress elicited by PQ as compared to mature cells. This may render immature brain cells more susceptible to the adverse effects of PQ.
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Impairment of human neural crest cell migration by prolonged exposure to interferon-beta. Arch Toxicol 2017; 91:3385-3402. [PMID: 28365849 PMCID: PMC5608792 DOI: 10.1007/s00204-017-1966-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 03/21/2017] [Indexed: 12/31/2022]
Abstract
Human cell-based toxicological assays have been used successfully to detect known toxicants, and to distinguish them from negative controls. However, there is at present little experience on how to deal with hits from screens of compounds with yet unknown hazard. As a case study to this issue, we characterized human interferon-beta (IFNβ) as potential developmental toxicant affecting neural crest cells (NCC). The protein was identified as a hit during a screen of clinically used drugs in the ‘migration inhibition of neural crest’ (MINC) assay. Concentration–response studies in the MINC combined with immunocytochemistry and mRNA quantification of cellular markers showed that IFNβ inhibited NCC migration at concentrations as low as 20 pM. The effective concentrations found here correspond to levels found in human plasma, and they were neither cytostatic nor cytotoxic nor did they did they affect the differentiation state and overall phenotype of NCC. Data from two other migration assays confirmed that picomolar concentration of IFNβ reduced the motility of NCC, while other interferons were less potent. The activation of JAK kinase by IFNβ, as suggested by bioinformatics analysis of the transcriptome changes, was confirmed by biochemical methods. The degree and duration of pathway activation correlated with the extent of migration inhibition, and pharmacological block of this signaling pathway before, or up to 6 h after exposure to the cytokine prevented the effects of IFNβ on migration. Thus, the reduction of vital functions of human NCC is a hitherto unknown potential hazard of endogenous or pharmacologically applied interferons.
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